I had a C128 back in the day. You could book it in C64 mode so was 100% compatible with all the C64 games myself and my brother had amassed. From what I remember there was little to none specific C128 games released. At least we never had any.
Yeah. The Rocky Horror Show is the only one that I remember having a C128 version and it was considerably better looking than the C64 version as well.