My copy arrived a few days ago... I still can't believe it actually turned up - I wrote the $80 I paid for the Japanese version off years ago.
I've had some issues however. The cart would not work on my Jap Mega Drive, nor my Wondermega... however, after reading about similar experiences on the Sega-16 forums, I hooked my Mega CD and the game then worked fine.
Also, the game will not work with my Retro-Bit controller plugged in, which is disappointing... and a bit odd, but whatever.
Had the loose heat sink issue - I've just removed it for the time being, will stick it down with gorilla glue at some point.
As for the game...
Graphics and sound are very impressive, gameplay I would say is average for a belt-scroller. It's more Final Fight 2 than Streets of Rage 2.
You don't have the moves of SoR 2, and the hits don't feel like they're really connecting at times.
If I was looking for a casual console play, I'd rather sit and spend half-an-hour with Final Fight Tough than Paprium.
I will say that the packaging is very impressive - the quality of the case and the manual are as good as any main stream developer would give, perhaps better in some respects.
I'm happy I finally got something to show for my money, but I wouldn't pay the $120+ they're asking for it now, the game just isn't that good. But, if you're looking for a new shelf warmer...