They show up. And damn do they.
end spoilers.
My gripes:
A) I don't like the level design.
1)There's too much crap everywhere. Obviously they did this to increase strategy, but it seems like they over-compensated.
2) They've made the weapons more powerful, yet the enemies are weak. SO they decided to just throw wave after wave at you. The first Halo was far more balanced. And its gameplay was graceful. This is just a mess.
3) half the levels are too dark to see what's going on even with the flashlight. And cool guy Arbiter doesn't even have a flashlight.
4) even if you CAN see what's going on, you still get confused because the levels make little sense.
B) There are some annoying bugs.
1)Every cutscene (for me) starts with like a 1/10 second shot of like pixelated animation. Almost like pre-production in movies.
2) Most of the time there is spoken dialogue, such as the cutscenes or when Cortana is talking to you, you can't hear what they hell they are saying because the music is too loud.
C) the story is god awful. When not totally incoherent, it's boring.
These gripes are just my opinion, obviously. But I can't help comparing Halo 2's campaign to, say, the prequels or the Matrix sequels. I guess it's tough when you're not allowed to do exact same thing over again for fear of being repetitive, and people are expecting you to top yourself. But still, it seems like Bungie totally lost track of what made Halo: CE such a great game, and instead threw every cool idea they could think of into a blender.