I'm very anxious to see how they'll make Halo. After all, it's more of a virtual game world, rather than a human acted movie. It's like Doom...enthusiasts of the game series might think it's not that great, because it's just weird seeing humans portray roles that are sometimes unnamed or unknown. For those who didn't play the game, it might be a interesting Sci-Fi/Action/Horror/Thriller. Depends.
The Simpsons: The Movie has it easy, because it's an animated movie, so everyone knows what the characters look like and they know what to expect. Simpsons = the town of Springfield and it's residents. It's not like having humans portray roles that are normally animated.