Serious Sam Collection achievements

Kill 100 enemies with Serious Damage active.

Complete the Persia episode in single player or cooperative.

Complete the Medieval episode in single player or cooperative.

Survive the storm on the Grand Cathedral.

Finish Serious Sam: The First Encounter

Kill an enemy with a gib torn from another enemy.

Decipher an Egyptian text.

Complete the South America episode in single player or cooperative.

Squash 10 Hatchling spiders.

Find at least 30 secrets in single player.

Secure the bird.

Find a secret under water.