Halo is a pretty average FPS.
STORY: The game is set in the future when the humans have conquered other planets and set up colonies on them. A cyborg soilder thing called Master Chief (not Chef) has been reseurected (for some reason) on a human space ship. He meets Captain Keyes. Captain Keyes is important. Very important. He also meets Cortana. A holographic space woman thing. The ship gets attacked by Aliens. Aliens blow up ship. Master Chief escapes (with Cortana). He lands, rather conviently, on a planet called Halo. The story begins...
GRAPHICS: I'm sure for the time these were great graphics. They seem to be very polished and have good texture quality and models. The animation however is not so good. The humans are animated really poorly in Halo, espicially during cutscenes. The aliens however are animated very well.
SOUND: The music is alright. The orchestrated songs are fine but the drum and techno songs are not so good. The voice overs are terrible and sound as if they have been taken from some lame action movie. The sound effects are good however. The weapons sound cool and unique. The alien vechicles also sound prettty good too.
GAMEPLAY: Halo has pretty average gameplay. It is very repetitive and very dull in parts. The game consists of achieving goals throughout a number of levels. It is just constant shooting. As there are barely any enemies (4 types of aliens of varying strength and weapons and 2 types of zombie enemies) it gets old pretty fast. There is no real strategy involved apart from "Kill them all or run past them?". The vehical combat is slightly more fun. There are a few vechicals in the game which you get to control. The most fun one is the flying alien thing which you can blow up things with. This is the only area in which Halo suceeds for me: the vehical controls. The vehicals control suprisingly well in this game. Not the best but still very fun and simple to control. The multiplayer (which apprantly 'saves' the game) is nothing special. It is fun for about 10 minutes I guess. Then it gets boring. It is way too repetitive and there is nothing special about. I had more fun playing Doom on multiplayer than Halo. The weapons in Halo is also kind of useless. Another feature is Halo is that you can only hold 2 weapons. Therefore it introduces strategy. I used human weapons through out the entire game (the pistol and shotgun espically) apart from some sections when you are forced to. Basically the humans have the good weapons (shotgun, pistol, assault rifle, rocket launcher) and the aliens have the crap weapons (plasma pistol, plasma rifle and needler). The alien weapons fire too slowly and are annoying to use. There are also 2 grenades in the game. Plasma Grenades (they stick onto things and blow up) and Grenades (normal grenades...they blow up). Both do equal damage but plasmas are effective as they are sticky. The level design is also pretty terrible with several sections being reused twice or more during the game. It can very confusing as it can be hard to find out if you are backtracking or not. Overall, Halo is repetitive and rather boring.
So there we go. Halo is very average FPS. I would recommend the Half Life series or Far Cry instead of this game. Halo isn't a bad game. It just is not a particulary good one either.