Serious Sam Collection achievements

Pierce at least 10 enemies with a single cannonball.

Awake the Guardian of Time.

Find Sam's classic outfit.

Kill at least 30 enemies with a single Serious Bomb.

Finish Serious Sam: The Second Encounter

Start the car.

Kill a Witch-Bride of Achriman.

Power up the Timelock.

Finish the Legend of the Beast campaign in single player or cooperative.

Solve the riddle of the Sphynx.

Kill an enemy using the Mutilator.

Defeat the spaceship.