Find a Key Card

Kill your first Face Hugger

Find the hidden weapon

Find the flame thrower

Destroy the eggs in all of the nests

Get scolded by Bishop. At least he likes your haircut.

Kill a Warrior or full-grown Alien with the Cattle Prod

Eliminate the Alien infestation

Kill the Queen in under 1 in-game hour

Escape from Fiorina 161

Finish the game without letting a single prisoner die

Have 5 Medi Kits in your inventory at once

Find the Base Map. T-minus 2:30 and counting...