Here is the full list of all 17 1 Bit Survivor achievements.
Survive Week 1
Survive Week 2
Survive Week 3
Survive Week 4
Get an A Rank
Get an S Rank
Beat the Game as the Survivor class
Beat the Game as the Assault Class
Beat the Game as the Hunter Class
Read the tutorial in less than 5 seconds
Take the easy way out
Roadkill 15 Enemies in a single run
Get 50 Knife Kills in a single run
Lose on the 28th Day
Complete the game with 9 or less Heals used
Complete the game with no upgrades
Pet Leo in the upgrade menu or main menu