The singleplayer is lackluster, like some other generic FPS, most of the levels are really disappointing, mainly because the level design is AWFUL.
My rant/review on Halo 2's single playerRustAngel, I like your name analogy. 2 levels on Earth sucked, mainly because most of the Halo levels were the same boring, generic crap we saw in the first game. 3 years and they can't fix the stupid level design. We actually went back to The Library!!! WHY!? In a cutscene, they said they were going to The Library, and MC was going somewhere else, and then you find out you have to go there as an Elite, wow, fun. Bungie took a shot at themselves, made me breathe a sigh of relief, and then kicked me in the nuts while I wasn't looking by going to the worst level from the first game as a character I don't want to play as. Playing as an Elite was cool for two levels, but they made you do it so much it turned out to be almost as annoying as playing as Raiden from MGS2. Then again, putting the MC on the cover in a prominent pose doesn't mean anything, hell in Halo 3 you'll probably be some generic Marine, like in THUG you don't even play as Tony Hawk anymore. Dear game devs, we want to play as the characters we know in love, that means no Elites and no Raiden. Bungie made so many half-assed mistakes in this cramped game with level design done by Stevie Wonder, because no person with vision could've made levels this horrible and cramped.
Halo 2 = Halo 1.5, because there's no way this game is a full sequel. They should've called it Halo: Island Thunder or Halo: Black Arrow, because it was more like one of those expansion pack type games than a full sequel.
But the multiplayer is fun, I only wish I preferred multiplayer to single player and I wasn't banned from XBL. Bungie sold out to the great Satan, and this lackluster game makes me hate MS anymore and I have lost much respect I once had for Bungie.