Discover all paths available in the game.

Finish the campaign at ARCADE difficulty.

Finish the game with a final score below 62,000 and the last score digit not equal to zero.

Nail down the opponent's head with the Pitter.

Kill all the Scientists at any chapter.

Finish the full campaign with your friend!

Devastate the opponent's body as much as possible!

Kill all the rats in the game.

Collect your first additional weapon.

Finish the game with a final score below 62,000 and the last score digit equal to zero.

Enter the secret room in Chapter 4.

Kill a Scientist.

Finish the campaign at any difficulty.