Yep, we always have those feelings. The demos are not good enough to show how much a game is fun or not. These are the things that drain your valuable MS points. These are the things that make you say "I could have got 4-5 rockband songs than this piece of s**t".
Cloning Clyde - Please, please, please. This game is linear as linear can be. This game is not fun. There is multiplayer, but is the same thing as single player but with a buddy, and your buddy will be asking you "Can we play rock band now?".
Small Arms - I am a bargain hunter. I thought this game was fun when I played the demo. Then it became an arcade hit and price dropped to 400 points. It is only fun for the while then it is only a waste of space in my hard drive.
There is my two cents for now.