Here is the full list of all 20 Bunny Battle Arena achievements.
LET MAIDEN MOAN 15 TIMES DURING THE INTRO SCENE.
LET MAIDEN MOAN 66 TIMES DURING THE INTRO SCENE.
COLLECT 66 MINIONS' SOULS WHILE FIGHTING A BOSS
COLLECT 666 MINIONS' SOULS WHILE FIGHTING A BOSS
COLLECT 666 AGILITY COINS
KEEP A TOTAL OF 66.600 IN MOTHER'S TEARS.
KEEP A TOTAL OF 666.000 IN MOTHER'S TEARS.
LET 66 BUNNIES' SOULS REACH REDEMPTION.
LET 666 BUNNIES' SOULS REACH REDEMPTION.
COLLECT 666 COINS OVER A BORCA'S BELLY.
JUMP ON A BORCA DEAD BODY 666 TIMES
EXPLODE 666 NUKES AFTER YOUR DEATH, WHILE USING DEATHMAGEDDON PERK.
JUMP AND LAND 666 TIMES WHILE USING ROCKET MAIDEN PERK
ACTIVATE THE POWER OF LOVE 666 TIMES WHILE USING LOVE ETERNAL PERK.
PLAY FOR 66.600 SECONDS WHILE USING THE CHRONOSPHERE PERK.
ACTUALLY PLAY SOCCER WITH BOSSES' HEAD 666 TIMES
KILL 6.660 BUNNIES
KILL 666.000 BUNNIES
LOOSE 666 TEETH.
ACELERATE 666 TIMES WHILE USING SPEEDY PIGEON PERK