You Had it Coming Achievement in Halo: The Master Chief Collection

Before anything, make sure to turn on "Scoring HUD" in the Campaign Lobby before starting a mission. In order to achieve the Par Score on all eight missions with Halo 4's Campaign, you will want to take three things into account.

First, manually activate the Cowbell and Grunt Birthday Party skulls in the lobby and set the difficulty to Legendary. You will probably already notice that these two skulls do not have beneficial multipliers, though don't let that confuse you. The former skull will make explosions a bit deadlier when combatting Covenant and Promethean enemies, while the latter skull will make Grunt enemies drop extra Plasma Grenades if killed via a headshot.

There isn't a necessity in turning on any of the scoring skulls during this playthrough since each of the missions in Halo 4 will grant you more than enough points even without any extra multipliers. Remember though, Par Scores cannot be obtained in Co-Op play, so just stick with a solo playthrough of each mission. This will also net help net progress towards the Lone Wolf Legend achievement.

Secondly, you will want to try completing the mission as quickly as possible (finishing under Par Time will give a x3 multiplier to your final score) while still killing everything on the battlefield via headshots and multikills; do not skip firefights or leave anyone alive. Lastly, if you do happen to run over Par Time, try picking up the pace as the time multiplier will begin to reduce significantly!

You can use the checklist below for a reference on each mission’s Par Score:

• Dawn - 25,000
• Requiem – 22,000
• Forerunner – 22,000
• Infinity – 25,000
• Reclaimer – 25,000
• Shutdown – 25,000
• Composer – 25,000
• Midnight – 25,000

Once you beat the Par Score for all eight missions, this achievement will unlock.