Summary
This is how an action-adventure should be like.
The Good
This game is one of the best examples of an action-adventure. It has everything: a fascinating story, great suspense and fantastic gameplay. The puzzles are action-oriented, hard, but always creative and not repetitive. Each combat is unique: although all (or most of the) enemies look alike, they are different: some are smarter than the others, and you have to use different kinds of weapons to kill them; also, you need to see each combat as a puzzle: each one requires a different approach.
The atmosphere of the hostile alien planet, where you have only one friend and have to fight for your live, is incredible. It's not just a stupid "shoot-'em-all" game, but an absolutely immersive experience. The graphics are fantastic for the age: the sound effects and the music are all in place, although there isn't much of them.
The Bad
The game is really, really tough: some levels are so frustrating, that it could take weeks until you solve all the puzzles.
The Bottom Line
A great action-adventure: there aren't many like this one.