Here is the full list of all 33 Boo Bunny Plague achievements.
Triggered Faye's transformation
Beat the game on Impossible mode!
Somehow managed to fall through the world and hit a kill zone
Collected All Audio Lore in one game.
Stun Thor 10 times with his own hammer.
Hit the giant donut!
Bounced on vikings 50 times
Destroyed all of the Bunny's in the factory
Watched the entire after credits scene
You collected all of the coins in the credits
Defeated the Chairman
Unlocked Impossible mode!
Defeated the Secretary
Defeated Heimdall
has defeated Thor, Garmr, Hel ,Tyr and Heimdall
Defeated Death
Defeated all Four Horsemen of the Apocalypse
Defeated Famine
Defeated War
Defeated Pestilence
Collected the Electric guitar.
Defeated Tyr
Collected the Frankenstrat.
Defeated Hel
Collected the Ice guitar.
Defeated Garmr
Defeated Thor
Collected the Streetz guitar.
Collected the Fire guitar.
Used Gunny to defeat an enemy.
Burn enemies 50 times.
Collected the "Useless" Acoustic
Defeated TRex