Great shooting game. Use a huge array of weapons, equipment, and abilities to fight off the alien forces and save the human race. Or you can become the bad guys and fight against the humans.

Controls
Movement - WASD/Arrow Keys (or Space to jump)
Aiming/Shooting - Mouse

Next/Previous Weapon - Q/E or Shift/Enter
Select specific weapon - Number keys

Use Ability - F/Ctrl

Pause - Esc/P