Here is the full list of all 23 Mayhem Triple achievements.
Walk Outside!
Just beat it!
Cause 20 enemies to be destroyed by testicle bombs.
Discover the secret to defeating the bunny threat and save the world.
Decapitate The Dire Bunny.
Destroy the helicopter in a special way.
Find the hidden greasegun in the "Prologue" chapter.
Find the hidden magnums in the "House of Cards" chapter.
Find the hidden Face-Trapper in the "Adobe Acrobat" chapter.
Kill a bunny in midair while diving and holding 2 weapons.
Kill 5,359.4 enemies.
Buy every available health upgrade and weapon holster.
Save a hostage.
Save every hostage in the game.
Kill 10 enemies with a single sawblade.
Stake 30 bunnies to a wall.
Score a perfect 10 in death.
Permanently kill the birthed alpha bunny.
Unlock every tontine treasure.
Get Georgia Close's number. You creep.
Find a better way to kill a mech.
Taze a crotch rocket.
Finish the game without health upgrades.