Okay, so once again I have a new addiction. Just when I was getting ready to give up on my cube a miracle is born. Metroid is a FPS that plays like no other FPS. The object is not to run in a blaze a glory. The primary objective is to explore and defend yourself. This gives the game a more realistic feel at times.
The controls are slightly different than most standard configs, but so is the game. BUT, they are VERY EASY to adjust to.
Gameplay is awesome, from sound to visual to feel, you completely envelop the experience. (My favorite is watch the water run off your visor as you jump back on to land.)
The exploratory focus lets you take your time playing this game. Other than a few timed areas/battles (which only add to the thrill) you will want to take your time and enjoy it. And relax if you miss something, this is one you'll probably replay for the hell of it.