The AI is sometimes braindead, the original unpatched version can crash at anytime and also certain pickups cause your system to lock up. And as far as gameplay is concered its quite linear. The game features excellent vibrant textures, lighting effects, explosion effects and various smoke effects. Also unlike many other engines, bodies,blood, and bullet holes stay permanently. The animation and character models and skins are very nice indeed and are pleasent to watch.
Sound effects are very good.
Although it is not a thinking mans shooter, its a lot of fun and always carries a very evil and disturbing atmosphere about it. The control is one of the bad parts of the game. You can't use the keyboard to well. Changing weapons is the same as it's been for the last 8 years. The saving factor for the poor aiming and shooting is actually the mouse.