Well, it's really good if you're into an action game that is really difficult.
I don't care what anyone says, getting out in time for that game is one of the most difficult game feats of ALL TIME.
The marine scenario was obviously the one that was the focus of the game, followed by the predator... the alien one was kinda thrown in for completeness.
As for the graphics, yeah for 2005 they haven't aged well.. for 1993 they're un-fucking-real.
A lot of people complain about level design, but take into account that the theme of the game is fighting it out in 3 ships in space. It's not going to be a sprawling planet. Also remember that it's on a cart... in the early 90's.... give it some leeway.
IT's supposed to be cramped.
THe atmosphere is good, damn good. If you want crunching guitars and thumping beats, go somewhere else... play this game hooked up to your stereo, with the lights out on a saturday night.. it's great in that atmosphere.
THe problem is you guys are spoiling yourselves with the Dooms, Halos and Half-lifes. This game is fun, hard as hell and old school.