Forget about all the reviews from 1999! This is a review from 2006!
However, in 2006, this game royally sucks. There is no depth into the game at all. All you do is move, spot enemy, kill enemy (or be killed), continue moving (or spawn), repeat over and over and over. It gets old really really fast
Maybe this sort of gameplay was acceptable 1999, but now? 2006? come on! I bought the game about 2 months ago, and after a week or two, it was getting really really old!
Here is another problem. The game was released 7 years ago. The people who are good at it, have gotten exceptionally good at it. The people who suck at it, have left it forever. This means you have no chance playing this game today. People now have 7 years of experience. Don't expect the games to be even close! You will just get kicked in the butt over and over again. This is seriously not fun. Unfortunately, the single player campaign is not fun either. The bots have inhuman precision, and are not fun to play with.
Overall, avoid this game like the plague. Maybe it worked in 1999, but today, it is hopeless.