I don't know why people are so addicted to this highly overrated game.
Here are some pros and cons that I can think of:
Pros:
1.Great multiplayer, packed with game modes, vehicles, and huge maps.
2. Lots of game modes; such as Forge, Deathmatch, CTF, or just normal campaign.
3. Really fun co-op campaign.
And that's all I can think of.
Cons:
1. Absolutely HORRIBLE single player campaign
2. Any other single player difficulty besides easy is torture; it takes like 50 shots just to kill a brute.
3. Dizzying campaign missions; wandering through the covenant bases and Halo facilities makes you nauseous.
4. Bad story; I have played all three games and I find that Halo 3's story is total bull****.
5. Weapons and vehicles needs to be more 'sci-fi and futuristic'; It is the year 2553, the humans have colonized numerous deep space planets and they are still using simple weapons like machineguns, dropships, and tanks. The only futuristic weapons are the covenent weapons and the Spartan Laser.
Conclusion: although I loved the online mode, I absolutely HATED the single player campaign. The game needs the short but action-packed campaigns from Call of Duty that has less meaningless story and more action. But overall, I'd say this is a pretty good game.
My final review:
Gameplay: 7.8/10
Story: 5/10
Graphics: 8.4/10
Funniness: 4/10 (only the naked man and the talking grunt kept it from being a 0/10)
Interaction: 6.5/10
Multiplayer: 9/10
Violence: 6/10
Unique: 5/10 (although the first Halo was really unique, being on a ring-world and whatnot)
Worth the price: Yes, but only for the multiplayer.
Final rating: 4 stars