Aliens: Dark Descent achievements

In any mission, complete at least one objective with only one marine in the squad.

Finish the game on Nightmare.

During a campaign, unlock every Xeno Tech.

Finish the game on Hard.

During a campaign, unlock every weapons.

Keep all of your marines alive during a campaign.

Advance a Medic to level 10.

Advance a Tecker to level 10.

Advance a Gunner to level 10.

Finish the game on Medium.

Advance a Sergeant to level 10.

Have one Sentry kill at least 10 aliens.