Halo 3 Achievement Guide & Road Map

Halo 3
Halo 3 Achievement Guide

Overview:
- Estimated Achievement Difficulty: 8/10
- Offline: 44 [1100]
- Online: 35 [650]
- Approximate time to 1750: 50+ hours
- Minimum number of playthroughs needed: 1
- Number of missable achievements: 10
- Do cheat codes disable achievements: N/A
- Does difficulty affect achievements: Yes
- Glitchy achievements: None
- Unobtainable achievements: None
- Extra equipment needed: None

Introduction
Welcome to Halo 3. There are a total of 79 achievements worth a total of 1750. It is possible to get all the campaign achievements in only one playthrough, but you'd have to play on Legendary, with the meta game scoring on, and looking for skulls/terminals. I recommend two or three playthroughs.

There are ten missable achievements: you have to find the hidden skull on each of the nine levels, which is one achievement per level, and you have to access all seven of the hidden terminals, which makes ten. You will unlock more than half of the achievements, 1100 offline, in either Campaign or Forge. The other 650 are online multiplayer achievements which can all be boosted.

Step #1 [Optional]: Campaign on Normal
Please skip this step if you are familiar with FPS games.

Basic Controls:
Melee
Reload (pick up gun/switch gun/get in vehicle/etc.)
Attack
Jump
Throw Grenade
Crouch
Switch Weapons
Use Equipment
Switch Grenades

If you are new to Halo or even FPS games as a whole, I would recommended playing on Normal for the first time. It will still get you a minimum of 405. You may or may not get the following achievements: "Too Close to the Sun", "We're in for some Chop", "Fear the Pink Mist", "Headshot Honcho", and "Used Car Salesman".

Step #2: Campaign on Legendary [Skulls/Terminals included]
I strongly suggest you play this in co-op instead of solo. It is much easier. It can be done online or local splitscreen. You will also be finding the skulls and terminals as well in this playthrough.

If you have two controllers but no one else to play with, you can make a co-op game with a guest and just leave the controller alone; every time you die you will spawn by him, and when you go too far ahead the game will load him next to you.

Refer to the guide for the locations of all the skulls and terminals.

Once you have beat Legendary, you will have a minimum of 785.

Step #3: Campaign Meta-Game
At this part you should have just about all the campaign achievements. To make it short, you are required to score a certain amount of points on each campaign mission. It's not the same on each mission.

I recommend playing on Normal with the skulls: Grunt Birthday Party, Tough Luck, and Catch. But of course it's all personal preference, so choose whichever skulls you are comfortable playing with.

Here is an outline of the meta game scoring.

Step #4: Online Multilplayer Achievements
Now, you should have all of the campaign achievements with the exception of Too Close to the Sun, We're in for some Chop, Fear the Pink Mist, Headshot Honcho, and Used Car Salesman. You should have a minimum of 875. There are 35 online multiplayer achievements worth 650. Some of them can be tough, but they can all be boosted. All ranked achievements, except MVP, must be done in the Lone Wolves playlist. All Legendary and Mythic pack achievements can be done in ranked or social matches in any playlist.

Step #5: Forge
This step should not take long. Simply go into Forge and play on each of the six Mythic maps: Longshore, Heretic, Assembly, Sandbox, Orbital, and Citadel. You will get the achievements for finding the skull in each map, each worth 25 and the achievement for finding all six skulls.

Refer to the guide for the locations of the Mythic Skulls.

The last Forge achievement requires you to kill someone while in monitor mode on a Mythic map. On any of the six Mythic maps spawn a tank and kill someone while holding it by slamming it into them.

Step #6: Mop Up
At this part, so you should have the majority of the achievements in Halo 3, if not all of them. The only achievements I can think of that you will still need to get are Too Close to the Sun, We're in for some Chop, Fear the Pink Mist, Headshot Honcho, Used Car Salesman, and Vidmaster Challenge: Annual.

Extra Info for the Extra 750G:

The Mythic Maps are: Orbital, Longshore, Heretic, Citadel, Sandbox and Assembly.
The Legendary Maps are: Ghost Town, Avalanche and Blackout.
None of these achievements can be gained on Heroic Maps, release maps or Cold Storage.
Here is a list of the possible gametypes in each playlist: https://www.bungie.net/online/playlists.aspx.

Conclusion
Halo 3 is overall a really enjoyable game to 1750. The only ones you might struggle with are the multiplayer achievements, but you can always boost them if need be.

[XBA would like to thank Slipknot1988 and Coadster1 for this Roadmap]

Landfall

20
Finish the first mission of the Campaign on Normal, Heroic, or Legendary.
(19)
See "Campaign Complete: Legendary" for tips.
Holdout

20
Finish the second mission of the Campaign on Normal, Heroic, or Legendary.
(7)
See "Campaign Complete: Legendary" for tips.
The Road

20
Finish the third mission of the Campaign on Normal, Heroic, or Legendary.
(5)
See "Campaign Complete: Legendary" for tips.
Assault

30
Finish the fourth mission of the Campaign on Normal, Heroic, or Legendary.
(1)
See "Campaign Complete: Legendary" for tips.
Cleansing

30
Finish the fifth mission of the Campaign on Normal, Heroic, or Legendary.
(1)
See "Campaign Complete: Legendary" for tips.
Refuge

30
Finish the sixth mission of the Campaign on Normal, Heroic, or Legendary.
(3)
See "Campaign Complete: Legendary" for tips.
Last Stand

40
Finish the seventh mission of the Campaign on Normal, Heroic, or Legendary.
(6)
See "Campaign Complete: Legendary" for tips.
The Key

40
Finish the eighth mission of the Campaign on Normal, Heroic, or Legendary.
(3)
See "Campaign Complete: Legendary" for tips.
Return

50
Finish the final mission of the Campaign on Normal, Heroic, or Legendary.
(2)
See "Campaign Complete: Legendary" for tips.
Campaign Complete: Normal

125
Finish the Campaign on Normal.
(8)
See "Campaign Complete: Legendary" for tips.
Campaign Complete: Heroic

125
Finish the Campaign on Heroic (unlocks achievement for Normal, if not earned).
(6)
See "Campaign Complete: Legendary" for tips.
Campaign Complete: Legendary

125
Finish the Campaign on Legendary (unlocks achievements for Normal and Heroic, if not earned).
(296)
It would obviously save you time to do all these at the same time by starting on Legendary, since the achievements stack. Going through on co-op with 3-4 people makes this extremely easy and shouldn't take you more than eight hours or so. Here are some general tips:
- Make good use of checkpoints. If you need to, run around and die once to get a feel for where the enemies are and what course of action you need to take.
- Be cautious once you know what to expect. Take it one enemy at a time if you can. Make good use of your grenades. If you have plasma or brute grenades, try to get a stick on one of the bigger enemies to take them right away. Some may require two, but it's much faster than picking away with a battle rifle.
- Let your NPCs do some work for you. They're not exactly powerhouses and you can't let them do everything, or they'll just run out and get killed, but they can lay down some initial fire and draw the enemies to them, then you can pop out and get more shots off without taking damage.
- Your shield recharges, make use of it. If you get hit once, more are sure to follow, so find some cover and recharge. The enemies will usually watch the area you went into cover, so if you can sneak around to another side from there, you can probably catch them off guard.
Note #1: The level achievements must be done in one go through or it won't register the achievements. In other words, don't save and quit in the middle of a level, wait until the start of the next level.

Note #2: You can not simply beat the last level on Legendary to get the achievements, each one has to be done. You can do some on co-op and some solo and it still works, just check that there is a shield in the bottom right corner when you highlight a level. You must even watch the opening cutscene on the same difficulty to unlock the Campaign Complete achievements.

Note #3: For additional help, check out our Legendary Walkthrough here.
Iron

10
Find and claim this skull when playing on Normal, Heroic or Legendary difficulty.
(17)
Mission: Sierra 117
Effect: "Death carries a heavy price..." -- Instead of only losing 25 points when you die, you lose 75. You also restart from the beginning instead of any checkpoint.

After Freeing Johnson and killing all the covenent that come in the phantoms, walk to the Pelican that comes to pick you up. Face the cargo bay but instead of hopping in, turn left and follow the path. Once you hit the wall jump up to your right, eventually reaching a walkway. Walk all the way to the end, take a left, then a right, then at the end of this little bit to the right is a dark corner. Turn your light on and you should see the skull. If you cant see it you're probably standing on it.

Refer to "Mythic" for a video of all the skulls.
Black Eye

10
Find and claim this skull when playing on Normal, Heroic or Legendary difficulty.
(1)
Mission: Crow's Nest
Effect: "Bash your way to better health." -- Your shield will not auto-recharge anymore, you have to kill an enemy with a melee attack.

From the start without moving anything you can see a massive pipe above you. Walk up the stairs then up the next set, turn to your left and jump up on the shelf unit. From there jump to the red cross beam then up onto the pipe, from there just walk to the end and walk over the Black Eye skull to claim it. You don't have to pick this one up it does it automatically.

Refer to "Mythic" for a video of all the skulls.
Tough Luck

10
Find and claim this skull when playing on Normal, Heroic or Legendary difficulty.
(5)
Mission: Tsavo Highway
Effect: "Your foes always make every saving throw." -- Enemies seem to avoid rockets and grenades easily.

After you have to deactivate a shield that's blocking the road, you will exit onto a bridge and a giant covenant ship flies overhead. You need to get out of your jeep if you are in one and go to the right side of the bridge, then go underneath and you will see bridge supports jutting out into the canyon. Jump onto the one farthest to the left and go to the edge and turn left and you'll see a small jut out of the cliff with the skull on it.

Refer to "Mythic" for a video of all the skulls.
Catch

10
Find and claim this skull when playing on Normal, Heroic or Legendary difficulty.
(21)
Mission: The Storm
Effect: "Pull pin. Count to three. Throw." -- Every NPC carries two grenades and throws them often.

You can get this by performing a grenade jump off a warthog, or grab a ghost and go back to the ramp from which you first came out, using the ghost to push a big square crate back over to the front of the silo that the skull is on top of, then use the box as a place to jump from.

Note: Destroying the second wraith by the door makes this disappear.

Refer to "Mythic" for a video of all the skulls.
Fog

10
Find and claim this skull when playing on Normal, Heroic or Legendary difficulty.
(6)
Mission: Floodgate
Effect: "You’ll miss those eyes in the back of your head." -- Your motion sensor disappears.

As you are walking down from the anti-air gun you destroyed in the previous mission, you encounter a ramp (next to a missile launcher). Around this ramp, you hit a checkpoint. At this point, you should also hear a marine yelling, “There! Over There!”. Look up and to the right, directly at the roof of the building next to the missle launcher. There is a single flood form (not to be mistaken with the two other flood forms jumping in front of you) which is holding the skull. Kill him before he jumps, and he will drop the skull down to the ground where you can retrieve it. Too early, and the skull will get stuck on the roof though, so just time it carefully.

Refer to "Mythic" for a video of all the skulls.
Famine

10
Find and claim this skull when playing on Normal, Heroic or Legendary difficulty.
(17)
Mission: The Ark
Effect: "Trust us. Bring a magazine." -- Dropped weapons will have very little ammo compared to normal.

When you first go into the valley to the right after the wrecked phantom, look to your left where you will see a huge boulder. Use a ghost and get to the side of the boulder that is closest to the bridge overhead. It is easy to pilot the ghost up the side of the wall using the thrust. To get the skull, pilot 2 ghosts up the wall to the top of the bridge and stack them one on top of another next to the beam where the skull is placed. Simply jump from the top of the ghosts towards the skull and land on the beam.

Refer to "Mythic" for a video of all the skulls.
Thunderstorm

10
Find and claim this skull when playing on Normal, Heroic or Legendary difficulty.
(2)
Mission: The Covenant
Effect: "Field promotions for everyone!" -- Upgrades enemies to their stronger versions.

After you shut down tower 1 and get access to the hornet, fly to tower 2 (the one the arbiter shut down). While walking up the stairs, go to the middle part that connects both and there should be a stair leading up to a platform where the skull is.

Refer to "Mythic" for a video of all the skulls.
Tilt

10
Find and claim this skull when playing on Normal, Heroic or Legendary difficulty.
(5)
Mission: Cortana
Effect: "What was resistance is now immunity." -- Enemies have different body parts that may be resistance to certain bullet types.

After you see a dead Elite with a sword on the ground, you will fall through a fleshy hole. You should be in a large room with a bunch of purple machinery. In the middle is a small purple pedestal with an arrow on it, pointing up. Jump on this, then look up to the left and jump on the rock formation. Look up and left again, then jump to that. Walk across the thin bridge and the skull will be on the ground here.

Refer to "Mythic" for a video of all the skulls.
Mythic

10
Find and claim this skull when playing on Normal, Heroic or Legendary difficulty.
(1)
Mission: Halo
Effect: "Coverage under the Covenant health plan." -- Gives a 2x score multiplier for all kills and doubles enemies health.

Follow the normal path till you reach a cave, then hug the right wall until it branches off into a small path, at the end of this path is some rubble and in front is the skull.

Note: The video below is for Halo 3 in the Halo: MCC collection and includes all skulls for that campaign (13 in all). The skulls are in the same location in this version of the game. Use the timestamps in the video comments to find the specific skulls for these achievements.
Graduate

10
Earn 5 EXP or finish 10 games to complete the requirements for basic training (Online).
(13)
You get 1 EXP point if your team wins in a team game (or if your team is in the top 2 teams in a multi-team game) and you get 1 EXP point if you are in the top half of a FFA match (5 players, top 3 get a point). You can earn points in both Ranked and Social matches. You will lose EXP if you quit out of a team match, so avoid that.

For this achievement, simply get 5 EXP or finish 10 games. You can lose all 10 and still get this achievement.
UNSC Spartan

15
Earn your Sergeant rating to be recognized as a true Spartan (Online).
(22)
For this achievement, you simply need 20 EXP.
Spartan Officer

25
Advance to the Spartan Officer ranks (Online).
(53)
Since the 25th of September 2008 the requirements for this achievement have changed.

To unlock this achievement you now need to reach 50 experience in any playlist, to earn the Lieutenant rank.

This will also unlock the “Vidmaster Challenge: Lightswitch” achievement.
Two for One

5
Score a Double Kill with a single spartan laser shot in a ranked free for all playlist (Online).
(678)
Your best bet for this is a King of the Hill game, seeing as everyone will be running into the same area. Hang back away from the hill and fire into it while people are vying for control. Not an easy thing to do, but keep at it. Best done at lower ranks.

Maps: Construct, Snowbound, High Ground

This must be done in the "Lone Wolves" game type.
Too Close to the Sun

5
Destroy an enemy banshee with the spartan laser or missile pod in a ranked playlist or in campaign.
(19)
In the campaign on the level "The Covenant" you start off with a laser and there are Banshees flying around in the sky. Simply keep firing until you get one and reload your last checkpoint if you keep missing and run out of ammo. Some people report having difficulty getting this even when blowing up a Banshee, but this is how I did it, so it does work.
Triple Kill

5
Kill 3 enemies within 4 seconds of one another in a ranked free for all playlist (Online).
(34)
This is best done in a King of the Hill or Oddball match, seeing as everyone will be running to the same area. Try to get a sword (this will get you the "Steppin Razor" achievement as well) or a rocket launcher. Otherwise, just get off some good grenades against people already battling and finish them off with whatever weapon you have equipped.

Maps: Any map, just takes skill and a little luck.

This must be done in the "Lone Wolves" game type.
Overkill

5
Kill 4 enemies within 4 seconds of one another in a ranked free for all playlist (Online).
(483)
See "Triple Kill" for tips. This one is decidedly harder since it requires you to kill all four of your opponents, but it does use the same principles.

This must be done in the "Lone Wolves" game type.
Lee R Wilson Memorial

5
Score 5 grenade sticks in any ranked free for all playlist (Online).
(36)
You have to get 5 total in a single match. Try to hang back away from people fighting and throw grenades in at them, or if you know someone has a sword, entice them to come after you and they should be lined up for an easy throw. The stick counts even if they die after you are already dead.

Maps: Guardian is by far the easiest.

This must be done in the "Lone Wolves" game type.
We’re in for some Chop

5
Destroy an enemy vehicle with equipment in a ranked playlist or in campaign.
(16)
In the campaign on Tsavo Highway, shortly after the second chapter begins, there is a long building to the left that has Trip Mines in it. Grab one of these and proceed to the next area. Here there are Brute Choppers trying to kill you. You will need to attack the front end of the vehicle for a bit until about two small pieces fly off. Once this happens, it should be weak enough to kill with the mine, so place it down and step behind it, waiting for the guy to try and splatter you. It may take a few tries, but just reload the last checkpoint if you fail.
Killing Frenzy

5
Kill 10 enemies without dying in any ranked free for all playlist (Online).
(71)
This one is somewhat difficult, but it can also be quite easy depending on your strengths and the skill of your opponents. If you're a good sniper, grab that and hide, only popping out to kill someone and moving spots whenever you shoot. Getting the sword or rocket launcher is always a good idea.

The way I got this: On Snowbound, grab the Spartan Laser and then hop in the ghost. Aside from the Brute Shot and Plasma Grenades, the enemies now have little defense against you. Keep circling the map and splatter or shoot anyone and use your boost to run away if you're getting hurt. I went 14-0 with this method. Lost the match obviously, but got the achievement.

This must be done in the "Lone Wolves" game type.
Steppin' Razor

5
Score a Triple Kill with the sword in a ranked free for all playlist (Online).
(109)
See "Triple Kill" for tips.

Maps: The Pit, Construct

This must be done in the "Lone Wolves" game type.
Mongoose Mowdown

5
Splatter an enemy with the mongoose in a ranked free for all playlist (Online).
(104)
This one is tricky. You will have to hit someone with low shields and at high speend for it to kill them, plus you have no weapons while on the Mongoose to defend yourself. Your best bet is to find two people fighting and barge in, hoping they don't notice you and you can get one of them square on.

Maps: High Ground, Isolation

This must be done in the "Lone Wolves" game type.
Up Close and Personal

5
Kill 5 enemies by melee or assassination in a ranked free for all playlist (Online).
(4)
Most of the battles in this game come down to an assault rifle spray and a beatdown, so this will most likely be your first online achievement. Sneaking behind people while cloaked will help as well.

This must be done in the "Lone Wolves" game type.
Fear the Pink Mist

5
Kill 5 enemies with the needler in a ranked free for all playlist or in campaign.
(7)
On the first mission of the campaign, you will come across a needler very early. Grab it and spray the next few enemies and you'll have this. Put it on easy if you're having trouble.

You can also do it online in "Lone Wolves" but it is much easier in the campaign.
Headshot Honcho

5
Kill 10 enemies with headshots in a ranked free for all playlist or in campaign.
(22)
In the campaign on the mission "The Ark" you start with a sniper. You will have to kill 10 enemies without dying for this. In the first battle (the circular prison yard), keeping firing on the enemies (with headshots) until it unlocks. Some people say they had to get only headshots to unlock it, but I killed one enemy with two body shots on accident, then killed two more with headshots and it unlocked.
Used Car Salesman

5
Destroy a vehicle that has three enemies in it in a ranked playlist or in campaign.
(12)
During the campaign you can get this by blowing up the area of a Covenant dropship (giant purple ship) where the turret is and for some reason it awards this achievement. Some people have got this by blowing up the front turret, some have got it by blowing the the side turret that is manned by an enemy, so try both. There are plenty of these ships in the campaign, any of them will work.
Marathon Man

40
Locate and access all Terminals in the Campaign.
(30)
Note #1: You have to wait for the "Fragment Ends" message to come on before the game registers that you've got the terminal. The only exception is Terminal #2 on the level "The Covenant," this one does not give that message. Hit the button to scroll through a few messages, then the terminal will turn red and a few more screens will need to be read before the "Fragment Ends" message appears.

Note #2: These can be done in any order and you do not have to finish the level. It is suggested to do them all on the same difficulty. Access the terminal, wait for the end message, then you can save and quit the level.

The Ark:
1. Start the mission and once you enter the first building take a left into another door and now you should be in a curved corridor. On the inside is a Terminal.
2. After activating the bridge to let your comrades across the gap, do a 180 and you should see it. *it does not open until you activate the bridge*
3. In the third building after defeating the scarab, kill the group of sleeping covenent, then follow the corridor downwards. Once you reach a door in front that is locked, immediately on the left there's an open door. Go through and walk straight off, then do a 180 to find a secret room. It is in there.
The Covenant:
1. When in the first tower standing on the lift, face the access panel and turn left. Jump over and it's right there.
2. Land your hornet on the second tower, walk towards the entrance but when you see the locked door, do a 180. Should be right in front of you.
3. When in the third tower standing on the lift, face the access panel and turn right. Jump over and it's right there.
Halo:
1. After reaching the end of the first cave, hug the right wall and you will see a building. Jump up onto the walkway and hang a left once inside. It's right there.
MVP

5
Earn the MVP in any ranked playlist (Online).
(31)
In a team match, the player who comes in first and gets the best Kill/Death ratio from either side will get MVP. So if the top player on team 1 has +2 and the top player on team two has only +1, the player from team 1 will get MVP. Your team does not have to win the match for you to be able to get MVP. This is only available in team games.
Maybe Next Time Buddy

5
Board the same vehicle within 10 seconds after being boarded in any free for all playlist (Online).
(104)
Fairly easy with Ghosts, just go up to people without splattering them and hope they take it instead of killing you, then there should a second or two before they can drive away where you'll be able to grab it back. You have 10 seconds which in a Halo online match is a long time, so pursue them if they run.

Maps: High Ground, Snowbound, Isolation

Note: This one can be done in social matches. Head to Rumble Pit with a friend if needed.
Guerilla

10
Score over 15,000 points in the Campaign meta-game on the first mission.
(27)
Please see "Reclaimer" for more information.
Demon

10
Score over 15,000 points in the Campaign meta-game on the second mission.
(3)
Please see "Reclaimer" for more information.
Cavalier

10
Score over 15,000 points in the Campaign meta-game on the third mission.
(1)
Please see "Reclaimer" for more information.
Askar

10
Score over 15,000 points in the Campaign meta-game on the fourth mission.
(2)
Please see "Reclaimer" for more information.
Exterminator

10
Score over 15,000 points in the Campaign meta-game on the fifth mission.
(3)
Please see "Reclaimer" for more information.
Ranger

10
Score over 50,000 points in the Campaign meta-game on the sixth mission.
(10)
Please see "Reclaimer" for more information.
Vanguard

10
Score over 50,000 points in the Campaign meta-game on the seventh mission.
(9)
Please see "Reclaimer" for more information.
Orpheus

10
Score over 15,000 points in the Campaign meta-game on the eighth mission.
(6)
Please see "Reclaimer" for more information.
Reclaimer

10
Score over 15,000 points in the Campaign meta-game on the final mission.
(18)
The meta-game is an overall score of how you do during a campaign mission. This thread on our forums has the scoring information, so check there for tips on how to get the required score for each level. Playing on harder difficulties, turning on skull and finishing quickly all give large multipliers to your score.

The "Bungie recommended" method is playing on Heroic with 1-2 skulls on. I personally did these on Normal with the skulls Fog, Catch and Tough Luck.

There are 7 achievements with a total of 250 points

Double Double

25
On a Legendary map, get two Double Kills during any ranked or social match.
(13)
Kill two people in four seconds of each other two times! Try using a power weapon (rocket launcher, spartan laser, etc) if you are having trouble with this. Must be done on a Legendary Map.
Alas, Poor Yorick

25
On a Legendary map, get 3 Oddball melee kills during any ranked or social match.
(82)
If you find an Oddball match, chances are you will get at least three melee kills with the oddball. The ball kills are varied. Sometimes they are instant and sometimes it takes more than two hits. This is unexplored as yet, but it may matter where you hit the player.
Came… From… Behind

50
On a Legendary map, get 3 assassinations during any ranked or social match.
(14)
You need to get three assassinations in any match. To assassinate someone, melee them in the back of the head. Can be made easier with active camo. Must be done on a Legendary Map.
Defend This

50
On a Legendary map, get a flag melee kill during any ranked or social match.
(30)
While playing a CTF match, grab the flag and attempt to kill someone with the flag. This can be made easier if you assassinate someome, as sometimes frontal flag melees won't kill. Must be done on a Legendary Map.
Flag Dropped

25
On a Legendary map, get 2 flag carrier kills during any ranked or social match.
(40)
All you need to do is play a CTF match and kill two players who are carrying the flag. The player who has the flag has a big shiny round blue arrow on their heads, making your task all the much easier... Must be done on a Legendary Map.
Road Rage

25
On a Legendary map, get 5 Warthog chaingun kills during any ranked or social match.
(31)
Have a teammate drive the warthog and you on the mounted turret. Get five kills (they do not have to be in a row). Make sure it is not a Gauss warthog (which uses a cannon)! Must be done on a Legendary Map.
Look Both Ways

50
On a Legendary map, get a Splatter Spree during any ranked or social match.
(94)
Use any fast vehicle (preferable NOT a mongoose) and look for people to splatter! If the vehicle has a boost addition, use it just before hitting a player. You need to get five such kills in a row. Must be done on a Legendary Map.

There are 13 achievements with a total of 325 points

Hammer Time

25
On Assembly, get 5 Hammer kills during any ranked or social match.
(44)
Get five kills with the gravity hammer. Unlike the above two achievements, it DOES NOT have to be a spree. Must be done on Assembly (Mythic Map Pack).
Post Mortem

25
On Orbital, get 2 Death From the Grave medals during any ranked or social match.
(83)
Get in the habit of throwing grenades. Lots of them! You have to kill someone after your dead. Another way of getting this without using grenades is by using a weapon that travels slowly or over a long distance (such as the rocket launcher of needler). With some luck, you should get this in no time. Plasma grenade stickies just before death are a very easy way to get this, but note that sometimes they won't count as Death from the Grave kills (Mythic Map Pack).
… Get the Horns

25
On a Mythic map, get a Bulltrue medal during any ranked or social match.
(28)
To get this, you have to kill another player who is in the middle of a sword lunge. You should use the shotgun and melee combo against a player (Mythic Map Pack).
Awww, Too Bad

25
On a Mythic map, get a Killjoy medal during any ranked or social match.
(8)
One of the easier achievements to get. Just randomly kill people and at some stage in the match someone will have a killing spree (Mythic Map Pack).
Killtacular

25
On a Mythic map, get a Killtacular during any ranked or social match.
(108)
The Killtacular medal is one step further when compared to the Overkill achievement. This requires that you get 5 kills in any match. However, this is substantially easier than Overkill because it CAN be done in social matches. Should be done in Grifball. Your opponents have a respawn time of three seconds instead of four, so you can spawncamp them and the kills will count towards your multikill (Mythic Map Pack).
Have Fun Respawning

25
On a Mythic map, get an Extermination during any ranked or social match.
(89)
The Extermination medal is awarded for wiping out the entire team with at least an Overkill. Very easy to do on Grifball, as multikills and exterminations are extremely easy to achieve (Mythic Map Pack).
Save This Film

25
On a Mythic map, get a Perfection medal during any ranked or social match.
(355)
The Perfection medal is awarded for winning a slayer game by more than 15 kills without dying or betraying someone. This should be boosted by a party as it is quite hard to get in ranked or competitive social. Try to stay back and let your teammates do the work, and occasionally popping out to finish off someone else's kill (Mythic Map Pack).
Delicious Brains

25
On a Mythic map, infect 2 humans during any ranked or social match.
(37)
Like Zombie Repeller, just the opposite. You have to be the zombie in an Infection match and kill two humans (the non-infected players). Try and get active camo, as it will make it a lot harder for humans to detect you (Mythic Map Pack).
Zombie Repeller

25
On a Mythic map, kill 2 Zombies during any ranked or social match.
(45)
In an Infection match, kill two zombies. Easiest done on the Braaaains gametype, as zombies have no shields, making it one hit kill with the shotgun or two bullets with the Magnum (Mythic Map Pack).
Tank Dropper

25
On any Mythic map, get a kill on another player while in monitor mode.
(22)
While in Forge, go into monitor mode and spawn any vehicle. Get another player to stand still (preferably) and swing the vehicle from side to side at his position until you splatter him/her (Mythic Map Pack).
Assembly Skull

25
On Assembly, find the hidden skull.

See the "Sandbox Skull" achievement for more details (Mythic Map Pack).
Orbital Skull

25
On Orbital, find the hidden skull.

See the "Sandbox Skull" achievement for more details (Mythic Map Pack).
Sandbox Skull

25
On Sandbox, find the hidden skull.
(23)

This video shows the location for the Assembly, Orbital, and Sandbox Skulls:

There are 7 achievements with a total of 175 points

Pull

25
On Citadel, get a Shotgun Spree during any ranked or social match.
(89)
Like Blades of Fury, you need to get a killing spree... with a shotgun. Must be done on Citadel (Mythic Map Pack).
Blades of Fury

25
On Heretic, get a Sword Spree during any ranked or social match.
(41)
You need to kill five players with the sword in a row. This can be made easier if you use active camo and it must be done on Heretic (Mythic Map Pack).
Ghost Patrol

25
On Longshore, get 3 kills with a Ghost during any ranked or social match.
(66)
Splatter or use the plasma weapon on the ghost and kill three people. This should be very easy if you know the basics of how to shoot and drive. Must be done on Longshore (Mythic Map Pack).
Citadel Skull

25
On Citadel, find the hidden skull.
(4)
Refer to "Longshore Skull."
Heretic Skull

25
On Heretic, find the hidden skull.
(3)
Refer to "Longshore Skull."
Longshore Skull

25
On Longshore, find the hidden skull.
(4)
This video shows the location for the Longshore, Citadel, and Heretic Skulls:
Vidmaster Challenge: Brainpan

25
Find all the hidden skulls on the Mythic maps.
(11)
Refer to "Sandbox Skull" and "Longshore Skull."

There are 3 achievements with a total of 0 points

Vidmaster Challenge: Annual

0
After 9/25/08, complete Halo on 4-player Legendary LIVE co-op, with Iron, and everyone in Ghosts.
(676)
You need 4 players to get this achievement and must be done on Legendary with the Iron skull. You have to start from the start of the level, not from Rally Point Alpha as the ghosts will not be there. You're whole team must be in ghosts at the very end (when you jump the gap into the frigate). For more information on where the ghosts are and other stuff, go here. To get members for your 4-man team to complete this achievement, go here. Here is a YouTube video guide:
Vidmaster Challenge: Lightswitch

0
Get to the rank of Lieutenant in any playlist in the new EXP progression system.
(18)
See the "Spartan Officer" achievement.
Vidmaster Challenge: 7 on 7

0
Enter into any ranked or social playlist with 7 EXP on the 7th of the month.
(36)
For this you have to make sure you don't have more then 7 exp in a playlist. On the 7th of any month, go into the playlist you have 7 exp on and this will unlock. If you have less then 7, just win a match (or more) and once you gain the 7th exp the achievement will unlock.