This is one of the best games on Xbox live and its a awesome game to buy. This game is worth to every Xbox 360 owner.
The campaign in this game was really good since it follow the cliffhanger in Halo 2 (If not, the best halo game to date) and it was worth it, you still face the same old enemies as usual, but the elites are now working with us. You could also play 4 player CO-OP online with your friends and its pretty good, can be a lagfest at times, but its fun, if not, one of the funnest campaign games out right now, you could play Campaign scoring with your friends and track down the skulls with them, after you track down the skulls, you could turn them on and have a great challenge with your friends on Legendary (CO-OP). The campaign in this game is only 9 hours, but it has great replay Value.
Then theres Matchmaking, now you could play stuff like Lone Wolves, team slayer, social slayer, MLG, and other cool stuff in Matchmaking. You could also meets lots of people on this playlist, but their can be lots of idiots online so yeah, but playing with your friends never gets on Matchmaking since you could play both Social and Rank by yourself or friends. Social is for people that wants to have fun. Rank is for people that cares about there rank, i think this is a great bonus for the matchmaking experience. Matchmaking is a great thing to play with your friends.
Then the phenomenal, Custom games. This is proably the best thing in Halo 3 (For the rate) since you could play lots of cool stuff with your friends with their Forge maps (I'll get to that later). Theirs nothing else but plain old fun in custom games with your friends or family members, its a blast.
Then the almighty Forge, you could create lots of cool stuff in Forge since its so much fun to play one. You could create lots of cool looking maps in it, like Foundary for example. I think this is a great feature in the game and its just fun to play on.
Then theirs Theater mode, you could just watch your games that you played today and watch them, you could take Pictures or Record videos and put them to your File Share and show your friends, this is one of the greatest features in the game and its just fun watching this with your friends. All i have to say that this is just fun to mess around with your File Share if your a Theater person.
Overall. This game is worth to every Xbox 360 owner and its one of the #1 games on Xbox live games now, go get it guys, its worth every penny.