Here's something I posted in another forum regarding the demo.
Getting bored with the demo might have something to do with there only being two levels, and both of those levels being the most bland levels in the game(the only unique aspect is the tower crescendo event.), the demo missing a few of the most revolutionary weapons(chainsaw&grenade launcher), and the difficulty being low even on expert because of the extra health packs, it is daytime so you hardly ever use your flashlight, and the fact that you find the more powerful weapons as early as the second level. To top it all off, there is no versus either.
So, to list all the things the demo DOESN'T include that will be in the full version- Versus Mode, Realism Mode, Survival Mode, Scavenger Mode, 5 full length campaigns, dynamic weather effects, nighttime/dark levels, both wandering and stationary witches, all the new weapons, all the survivor lines, different style finale events(think running across a bridge while being bombed), and dynamic routes(like shortcut you take in one game but the next it's barred up with plywood or a fence).