'Twas fun
It's weird, playing that game, because there are moments where it goes from the screen to your eyes to your brain and to your fingers all zen-like without any effort (like those last two songs, for whatever reason) ... and then there are those moments when it all goes to hell and you're clamming every note/chord and you're struggling to catch up and make the "connection" again.
I think at the end there, your hands were just getting too tired. Cowboys from Hell in the final set is rediculous, btw. I went back and replayed most of the songs (going through my old band saved-game).. and that one in particular was kicking my ass. Ace of Spades was a bit rough as well.
Playing the game on Hard or Expert has to be absolutely insane. It'd be one of those situations where you pretty much have to play/replay a particular song enough times to more or less memorize it. It's just too crazy to actually follow along with the notes.. let alone with the extra pinky button (one pinky-stretcher is fucking hard enough!)
All in all.. the game is entertaining, and would likely be extended-fun with the dueling guitar contests.. but I have to admit I was a little disappointed in the overall depth of the game. The different characters you "unlock" really don't mean anything, nor do the different avatars or guitars have any varying impact on the game. It would have been nice to see some kind of positive reinforcement for messing with those options and earning better equipment with your hard earned loot.