I saw some videos for that yesterday, and thought it was brilliant. I'm a big fan of the C64 and Retro Computing in general, and I also have three Guitar Hero games.
I was dissappointed that the game doesn't come with some classic SID tunes (like ones from Hubbard and Galway), but you can make your own up from existing SID files.
It's amazing that I can use my guitar on my C64 now, but I still can't play my three Guitar Hero games on my PS3 (only on my PS2), because no-one has made a fully compatible adaptor!

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