Complete level 7.
Kill 750 enemies.
Complete level 6.
Complete level 5.
Kill 500 enemies.
Buy any cat upgrade.
Complete level 4.
Complete level 3.
Preform an UltraViolence kill combo.
Kill 250 enemies.
Complete level 2.
Kill 100 enemies.
Preform a Brutal kill combos.
Kill 50 enemies.
Preform a Cruel kill combo.
Kill 25 enemies.
Complete level 1.
Preform a Deadly kill combo.