Got in the motherlode today:
All X68000 games:
Valis 2...
You had me at "Valis 2"... Please do a very thorough review and post it here for me. I'm pretty sure you played through the PCE Valis II. If so, compare/contrast, when possible!
GODDAMN, all those classic games on the X68000.... 
X68k Valis II has very nice graphics, smooth scrolling, and fantastic music. However the control is beyond terrible, the worst control in the entire series, and that's saying something. You are essentially locked to a grid (think Tomb Raider), but no "walk button" so you constantly run off platforms to your death, plus UP to jump and you need good momentum or you will not make the jumps. The music is so good I keep playing it anyway though.