Megalo Syuuto Achievement in Vampire Survivors

For both of these achievements for defeating 100,000 enemies in a single run, they can be done on any stage. So, feel free to be as safe/conservative as possible, picking, for example, Inlaid Library and activating Endless Mode, and just waiting it out until you kill 100,000 enemies. However, if you want to knock these out as quickly as possible, start up The Bone Zone with Hyper and Hurry activated (as well as Limit Break and Arcana, of course). Pick the Arcana to increase Greed, Growth, Luck and Curse every level, and consider also picking up the Skull O'Maniac and Torrona's Box, upgrading both. This will drastically speed up how quickly you get these done, assuming you're confident in your build. You should be good from the base game, but just to reiterate:

• Santa Water + Attractorb
• Axes + Candelabrador
• King Bible + Spellbinder
• Lightning Ring + Duplicator
• Song of Mana + Skull O'Maniac
• Starting weapon evolution (see Boo Roo Boolle (5G) for how to evolve it)

Optionally, if you have tons of money built up, get five weapons and then buy all five weapons from the Vizard to have nine weapons. Once all are maxed out you'll be unstoppable.

Once you reach 100,000 kills, you will likely need to just quit since you'll probably never die.