Successfully complete the indicated task to unlock the corresponding achievement.

Achievement	How to unlock
...Two legs at day...	Complete the Day segment of the game.
...and three legs at Dusk?	Reach the end Boss.
Architect of Doom	Publish your first level on the Steam Workshop.
Don't forget to rate!	Beat another player's Steam Workshop Level.
I'm Immortal!	Beat the postgame levels.
One Man Apocalypse	Why won't they stay down?
Overkill	Fall from a high height into water while also dying of poison.
Stayin' Alive	Completed a level without dying. No corpses.
That'll leave a mark.	Fall onto the flag at termnial velocity with no lives to spare.
The Organic Titanic	Her voyage couldn't even last 10 seconds.
What walks on four legs at dawn...	Complete the Dawn segment of the game.
You get used to it.	Die 1000 times.
Zombies are overdone, anyway.	Beat the end boss with fewer than 6 of your corpses shambling about.