I can't believe I'm saying this, but I also may be going to bed early so I can get up and play for an hour or two before work. I've never done that for an XBLA game before, but for some reason I'm more excited for this than...uh, just about any other game on the 360. I dunno.
Yeah, we'll all be sick of it in two weeks, but for now it's great. Especially for 5 bucks.
Also, for those who were discussing the certification process and the developer using it as a scapegoat: obviously it's a case-by-case basis. However, don't be so quick to pass judgement on everything else just based on this.
It's VERY likely that this has been in development for a while now, and has just been kept quiet until the movie got closer. Remember how Doom showed up out of nowhere last year during E3? They're not totally inept at keep some stuff a secret. I have a feeling this has been in the works for a while, and finally someone let the cat out of the bag a few weeks ago before the official MS announcement.