I've played this. It was pretty horrible to be honest. Everything about it just felt cheap and amateurish. The Gamespot review is pretty spot on, and my major gripe with it is that there are enemies that can kill you, and you have no way of defending yourself against them. Basically, this user comment from Gamespot is pretty accurate:
"This is what Portal could have been like if Valve had failed miserably!"
I would definitely avoid it.