Good side scrolling shooter based on Aliens. Simple controls, movement, shooting while standing, and shooting while ducking. Rapid fire gun can be upgraded into a flamethrower, seeking rocket launcher, or a spread shot. Can pick up some mostly useless bombs that it will throw when you push the shoot while ducking button. Mixes things up with vent segments and turning into a vertical shoot em up at some points. Good, though strange, enemy variety. Not made to be overly difficult.