Graphics are dated, but good enough. Challenging fun without complexity of squad tactics, etc.
The background ambient sound is repetitive. If you can just tune it out it won't bother you too much. The "bullet time" kill shots are cool to watch and are like a little real-time reward for good aim.
On today's machines you can crank its graphic settings way up and get a decent visual experience, but don't expect too much. Also, although it is dated, it loads and plays well on a Vista box.
Finally, as others have said, this seems to be the best sniper style FPS to date. Given the quality of this one from a few years back, it would seem time for a Sniper Elite 2! Since it probably wasn't played that much in its prime, a simple remake using a current framework/platform would be a welcome addition to the market.