A solid game that just somehow manages to be really fun.
It's that everything is really solid. The weapons feel great, the control is nice, and the HUD really works well. Vehicles work surprisingly well and are controlled quite differently from other games with vehicles (takes a bit of getting used to if you're new). The AI is really good as well; the enemies are realistic in the way they act. The game takes place in the future but it's not totally a run and gun shooter but its not completely tactical either. It's a very good mix and it's one of the main reasons why the game works out so well.
The story is also something to take note of. It's really well done and the campaign works out really nicely. I especially enjoyed fighting the covenant and the last timed mission is a great way to end the game. I, however found the game surprisingly short. I never played Halo for the xbox but I played Halo 2. Everyone complained how short it was in comparison to the original Halo. I found Halo 2 a descent length for a fps. However, I found Halo: Combat Evolved, the same length or even shorter than its sequel. I beat the game in one day (I don't think I ever did this before with a full length game). I played a lot of it but I still only got 7 hours out of the campaign on the first run.
The multiplayer is also really well done. It's one of the reasons why Halo 2 is so popular for the xbox. What's more fun though is the lan. Most of my hours probably went into playing lan into the game. I wish there would be bots in this game but even without any, the game is still enjoyable. The game's style just makes it a fun game to play with friends. Also, lan is a great choice because you can get around the lag issue that's online. I experienced pretty bad lag online. A 'good' server I went to, most people had 220 ping or more. And that's one of the better ones. The game just has a terrible anti-lag system. It takes quite a bit away from the experience but the game does have a bit more content in the online portion compared to the xbox version.
Overall, Halo is just a fun game to play, especially with friends or just replaying the campaign. The great campaign and gameplay really boost the value of the game and the multiplayer aspect doesn' hurt either. The singeplayer could have been longer and the online experience could have had better anti-lag support and servers but other than that, it's defiantly a solid game.