This game combines fantastic ideas, an alien world full of life, great AI, excellent rendering engine which combines the powers of raytracing and normal polygon rendering. The soundtrack is awesome and the gameplay highly addictive.
It is a mix of action, adventure and RPG perfectly balance to give the player the best gaming experience. A lot of work went into creating this game and it really paid off! Also look at the Wikipedia article for a link to the unofficial patch which allows you to run the game in 640x480, avoiding the black frame!