Kill a Stalker with the Seeker Rifle while in Zoom Mode

Collect 10 Schematics

Kill 4 enemies with the same Ripper blade

Survive your first encounter with Stalkers

Get through the first Zero-G area

Impale an enemy into a Decompression Window to cause it to blow out

Impale an enemy with the Javelin Gun and use its Alt-Fire to shock 3 others (single player only)

Survive the Train Sequence

Get your first Suit

Kill a Brute without taking damage

Severed: Kill 16 or more enemies in the final last stand combat sequence

Use Quick Heal ten times (single player only)

Severed: Take out the gunship within 30 seconds