Good campaign and multiplayer
The campaign is medium in length but it has the Heroic and Legendary difficulty which are much more challenging to complete than Normal. Its campaign packs a great storyline and it is lots of fun.
The multiplayer is also great. It has 6 more maps than Halo for PC and it also has the Flamthrower and Fuel Rod Gun. Also the Warthog with a Rocket Launcher is also available. The multiplayer will give you hours after hours of fun and excitement.
Halo is great and it doesn't lag much considering its requirements are pretty low compared to other FPS games. I would definitely get this game as it is a classic.