Hey Pap64, I've watched a few of your videos on YouTube, and this game does look rather interesting. I don't mind so much about not being able to write your own music if there are lots of ways to remix the included tunes. This game still looks like fun and is becoming rather enticing...
So... how many tunes are included in Wii Music anyway?
50 songs.
Many of them are public domain songs. Keep in mind that when the game starts you only have 5 songs, and you will remix them over and over till the game tells you that you are good enough and gives you the other set.
This doesn't take long, though. This takes around an hour and that time is spent training so you understand what the game is all about. Once this is over you should have a better idea of what to do in the game.
The game has a lengthy and deep tutorial regarding the music genres and remixing tips. I think you could be a while in training (don't worry its all optional).
Thanks for watching my videos! I would upload more but I'm not happy with the quality.
Note that the game uses the Wii's own friend code, so if you ever get Wii Music make sure you have us registered as Wii friends.