Here is the full list of all 40 Bloody Zombies achievements.
Explode kill 50 zombies
Complete level 6
Finish a level with a Golden Pigeon
Buy something from a shop
Complete Level 1
Play a multiplayer game online
Reach a hitstreak of 100
Collect a skill
Find the statue secret in level 1
Find shop secret in level 2
Kill a zombie using a dinosaur
Disable the museum security under 60 seconds
Find the teachers Lounge in the school
Reached the end of the game
Unlock the true ending
Reach the park chest
Find the first secret keycard
Find the second secret keycard
Find the third secret keycard
Find the fourth secret keycard
Find the fifth secret keycard
Find all secret keycards
Reach a hitstreak of 500
Revive a player in multiplayer
Grab a Golden Pigeon that has been knocked off another player
Finish a level without losing your streak
Earn an S rank on any level
Finish a level in 1st place while playing multiplayer
Kill 4 enemies with a single attack
Upgrade a skill to max level
Unlock every skill
Get S rank on every level
Pogo 3 times before touching the ground
Reach the end of the train without being hit by a sign
Destroy an explosive only destructable
Beat the final level without dying
Discover the train secret chest
Superdodge 30 times
Finish the game in Hard mode
Finish the game in Insane mode