I had no say on the song choice in the game, sorry, guys...
Smash Hits, Metallica, and Van Halen are modifications of the GH4 engine... ours is probably better looking and less buggy than any of those games since we had more time.
Our game can be obtained with GH5 for free for a certain time, before the game's true release in December 22 (why then? It's because our marketing dept. is silly :|)