As both an entrant in and fan of the Project Eden music game contest over at Kongregate (which I won't directly link to, because I've annoyed everybody enough with that), I've noticed something about a specific kind of game, and this blog is just going to be me getting a very strong opinion off of my chest. 
 
Games that create levels based on music are never as much fun as they seem on paper.
 
To be clear, I mean games where you import an mp3 or other audio file from your music collection and, somehow, the game analyzes it and makes a level based on it. Audiosurf was kind of the first notable game to do this (unless you want to point to Vib Ribbon, which I haven't played and can't comment on) and The Polynomial was the last one that I know of to do it well. Even The Polynomial is best enjoyed when you turn it into a non-game.
 
I love it when music is integrated into gameplay. Rez and Child of Eden are my two favorite games and I think they're really special experiences. The trouble is, most games that procedurally generate gameplay from music don't really enhance the experience of either the music or the gameplay. I always find them to be totally underwhelming and the gameplay that results from whatever music you feed into it just isn't strongly associated enough with what's going on to make it feel like it mattered what you loaded in. Most of the time it feels like I might as well have just played Asteroids while listening to my iPod. 
 
So, unless someone really figures out something neat to do with it, I'm pretty sick of seeing games with music as input. Games with music as output, on the other hand (Rez, Child of Eden, Lumines, etc), are more compelling across the board, in my opinion. A reward of beautiful music for my in-game actions can make for a much more resonant experience than any sort of competition or narrative. It also makes the connection I have to the music much stronger, as evidenced by my disinterested in Genki Rockets but love for Child of Eden. 
 
Opinion blog over! I'm going to go eat spaghetti!