I've bought quite a few of the commercial games and they range from crap to great. None of them have graphics that really show off the GP32, infact some look worse than emulated PCEngine games
I don't have Pinball Dreams as it's not really my thing, I've played the demo a bit and it's ok I guess. Some people swear by it..
Tomak was hyped up a bit, but I think it kinda sucks.. Bad frame rate and mindless gameplay. It doesn't really feel as though you're having any impact on what's happening, meh..
I didn't like GP-Fight at first, it's quite difficult. The first level is frustrating but once you get past that it's really fun.. The graphics are nice and remind me of River City Ransom on the nes a bit. Definitely worth getting in my opinion.
Mill is good, but I've found quite alot of (reproduceable) crash bugs (haven't tried the patch yet, so hopefully it fixes them). It's a fun game, sort of a cross between Zelda and Princess Crown on the saturn.. I REALLY hope it gets translated, more so than ASR. The graphics are good, but I wish they were more animated (water falls/rivers are static, etc which looks silly).
Little Wizards looks great in screenshots but plays as if it's at "frameskip 20". It feels like 5fps at most. It's actually a fun game with nice character designs, etc.. But the frame rate ruins it for me. It doesn't bother some people though, so maybe I'm just a neogeo snob.
ASR is nice, and plays a little like a Shining Force game. Great looking, but I'd rather play an english Shining Force game on the SMS emulator.
I don't really like Her Knights, I tried to like it.. I really tried.. But EVERYONE else seems to love it.
"Dyhard with infinite stairs" has the best title ever, but is trash. Don't bother. Well actually it's not terrible but maybe not worth the 14,000 joygp are asking. If it was 8,000 like the Hany games then it would be a better buy.
The two Hany games are really fun. They're worth getting if you want something cheap and fun. The puzzle one is better than the tower one (which is fun, but gets old).
Kimchi Man is alright. It looks nice enough but is not really my thing. Same with Super Plusha. They're both programmed competantly enough but the design is lacking
Rally Pop is ok, and has a really nice style (in my opinion). It gets old pretty quick though, I'm sure it's fun in 2 player linkup/rf mode though..
Anyway, give GP-Fight a chance. It's the best looking/playing GP32 game in my opinion, followed by Mill.