You are on a mission to explore the orbital outpost and wipe out all alien activity. Invade a building full of aliens, walking the labyrinth and being alive to be able to complete the stage, picking up cards on the floor that are used to open doors. When you do not have cards, you can blast through the door until it opens. Try to destroy as many enemies to increase the patent and to buy better weapons. If you run out of ammo, use the pistol, but flee from bigger enemies.
WASD / mouse. Space to reload / perform action, shift to select your weapon. P to pause.