Wii!!
I haven't touched MP yet, except to take a break to run around a few maps and poke at the forge and download a few movies to watch - oh, IS THERE SLIGHTLY JUST A LOT TO DO IN THIS GAME YES SIR MAYBE THANK YOU MA'AM?
*cough*
Anyway, campaign, on Heroic, for me at least feels like everything that was cool about Halo 1 with just the bare ghost of Halo 2 in there, and next-gen shine added. I'm glad they turned on the motion blur, subtle as it is; at this point it is something that adds an extra sense of reality that's nearly subconscious.
As for the debate over the frame rate, to me it feels like the beta but just a touch more polished. What I'm seeing most of the time isn't really frame rate sluggishness, such as chugging along at 25fps for extended periods, but more like "hitches" that happen at totally random moments. Given how smooth cut scenes are and how smooth movie playback is, I have to think that this is from the AI or something when the game is being run in real time. However, especially with the motion blur in, it really is not bothering me. It doesn't feel as if the engine is underpowered and struggling; quite the opposite, this damn engine feels as if it could vomit forth the hoards of Genghis Khan at any moment. But it's just a touch jittery. I can live with that.
(Especially compared to Gears, which can't run a scripted cut scene at 30fps with 3 characters on screen.)
The one thing standing out to me was actually the score so far. It's really awesome, seems more dynamic, and actually feels as if Marty avoided falling into his own Halo cliche. I'm more impressed with it than Halo 2's score, which felt as if it /was/ lifelessly imitating its own stereotype from the first game.