Jeremy McGrath Supercross 2000 [NTSC-U]: Not working. MESS plays the audio for the two intro FMV's but never shows any video. Eventually the music stops and your stuck at a black screen and none of the keys do anything. pSX shows both intro FMV's and lets you press a key to pass the second FMV but then hangs at the start screen because it is not recognizing input either.
Diablo [NTSC-U]: Not playable. Shows the Blizzard / EA copyright screen and then goes black and never comes back. Seems to work fine in pSX - although either the graphics / controls are glitchy or it was a terrible port. I'm betting the latter.
Groove Jigoku V (Japan) [SLPS-01205] - seems to work, at least the minigames I tested although it's weird...
Genei Tougi - Shadow Struggle (Japan) [SLPS-00491] - gets stuck on 'now loading' screen after starting a new game, it starts playing an audio track (well the data track as audio, then the audio) but goes no further.