Enter the secret room in Chapter 4.

Don't destroy any glass panels in Chapter 2.

Shoot down 50 enemy projectiles.

Finish a chapter without reloading with bullets in the chamber.

Kill all the Scientists at any chapter.

Finish the campaign at any difficulty.

Beat the Magician at the end of the fourth chapter.

Beat Hangedman at the end of the second chapter.

Save a Scientist.

Kill 3 enemies in a row.

Complete the Water Plant Level without touching any of the electrified water pools

Find all four floppy disks

Go heckin' fast while sliding on dangerous ice!