Dismember 1000 limbs from living enemies.

Save your Co-Op partner from an execution by killing the attacker.

Use the RIG to give an item to your Co-Op partner.

Defeat the Moon.

Kill 10 alien Necromorphs.

Dismember 500 limbs from living enemies.

Find Peng.

Kill the Snowbeast.

Kill a Soldier by TK'ing a grenade or rocket back at them.

Recover the shuttle.

Use quick heal to heal yourself 20 times.

Craft a Weapon.