There is an old PC game that plays similiar to this:
http://www.gametrailers.com/video/debut-trailer-capsized/57594
except it was much darker and I THINK it had Aliens (rip off version) in it. I know you used the arrow/wasd keys to move your character and you used your mouse to aim and shoot. But it was a sidescroller and seem to recall it was like metriod like games too. This game trailer totally made me remember this although this game looks more colorful and puzzle solving.
http://www.gametrailers.com/video/debut-trailer-capsized/57594
except it was much darker and I THINK it had Aliens (rip off version) in it. I know you used the arrow/wasd keys to move your character and you used your mouse to aim and shoot. But it was a sidescroller and seem to recall it was like metriod like games too. This game trailer totally made me remember this although this game looks more colorful and puzzle solving.