No missable achievements (plus 38 unknown)
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You bested Chainsaw Megamaniac! There's no chainsaw maniac tougher than this one.
Destroy a breakable wall.
You bested Big Bat! Have you ever seen a bat so big?
You bested Green Hydra! Two heads are better than none, but that won't slow us down.
You bested Red Devil! Yow, it's hot in here!
You bested Eyeskuller! Eye spy with my little eye something that's about to explode!
Destroy five hanging skeletons before they hit the ground.
Make Chainsaw Megamaniac leave his chainsaw behind when he dies.
Knock five spiders off the wall.
Wake up 6 sleepy frogs.
You bested Manleech! Say your lamprey-ers!
You bested Blue Devil! Necessity is the moth of invention.
Watch Manleech vomit 10 times. Yucky!
Run away from a crow for a very long time.
Beat a world without taking a hit.
You won as Pumpkin Man! Get pumped!
Get grabbed by Blue Devil three times.
Trigger spike traps 101 times.
Never harm little bats! Ever!
Beat the game with 1 HP Mode enabled! HARDCORE!!!