Survive the avalanche

Beat all the levels in "Knee-Deep in the Dead"

Fully mod and completely upgrade any weapon.

Crush a corpse in a door

Perform 50 headshot kills in the single player campaign.

Get full combo on any level on expert difficulty without any modifiers.

Clear all missions in campaign.

Kill 25 unaware enemies.

Loot 200 enemies.

Find 25% of all documents.

Perform 15 finishers.

Clear 100 levels or more.

Complete one optional tomb.