It's an old game but it can still be fun many years after it was born.
While playing, I intentionally tried to remember this was a game from 2004. It's definitely old by today's standards. However, that doesn't mean that what you get, even now, isn't worth a run through. In fact, generally speaking, I enjoyed my time playing through this one despite it being dated, a bit glitchy, and showed its age in a few spots.
The story itself is a bit mundane but it was a nice touch to jump back/forth between the good guys and the bad guys. Yet, like others have commented, the sort of abrupt ending was a bit odd and seemed rushed. That's disappointing for a series of this caliber and its too bad they didn't do a better job. At the end I didn't feel fulfilled and excited to move on to the next game. Rather, I felt jipped. I didn't even get to be the main hero for the end of the game. What's up with that?
I'll admit to being a bit frustrated a few times on this one. In a few segments I found the swarms of enemies a bit annoying. Oddly, much of this is simply due to the fact that the game wasn't as realistic as things are today so your expectations of AI movements are not always as accurate as one would expect. Random monsters would spawn out of odd locations and jump you and various sorts of things.
Ultimately, the pace of the game kept me going until about 3/4 in. Though a short game, I started getting tired of playing and ready for things to wrap up. There just wasn't enough variation in the level design to really keep you motivated. Yet, for the original 2004 launch, it is certainly a solid piece of work.