Killed 5 Rakk in under 10 seconds

Earned level 5

Completed 5 missions in the Arid Badlands

Finish the game in Normal Mode

Release Melissa from her Trap.

Find 90 treasures

Complete any level (except bonus levels) in frozen state in Arcade mode or in Co-op Arcade mode

Complete all levels in "Arctic" episode

First kill with a Gun.

Release Jennings from his Trap.

First kill with a Nail Bat.

Unlock 5 locked doors.