Whatever flavor of Gens that Eke-Eke works on (Gens32 Surreal, I think) the latest version of it should support this game unpatched.
I've just slapped a few things onto the ROM based on the protection routines he found when updating the emulator to emulate the copy protection natively. It's not completely fixed; if it was then it would work on flash cartridges and copiers, and I guess these bugs are probably what's causing it to hang/crash it some emulators.
So the way I'm looking at this I'm placing this around late '97. The engine is a bit more polished than Soul Blade or Samurai Spirits II, but not nearly as good as KoF '98. Not sure if it came before or after MMPR. You'll also notice some fonts and HUD items that are carried over (or copied from?) X-Men VS Street Fighter for SNES.