Take care of an alien infestation, make sure that they will never return.

Instructions:

Use the arrow keys or the WASD to move around.
Use the mouse to aim and fire. The green dot to determines the perfect moment to fire. Try to aim for the head.
R to reload.
Press space to open a door.

Press 1,2,3 to select weapons.
4,5,6 to use special skills.
Press C to go to the upgrade screen when you have levelled up.
Press M to use a medikit.