METAMORPHIC FORCE / Konami / Arcade
Metamorphic Force appears to have been made by the same team at Konami that did the equally obscure (but quality) arcade game Mystic Warriors. Art style looks the same, bosses have the same Engrishy taunts, cut-scenes have the same sort of hilarious misspellings and bad grammar, etc. Instead of being a modified run-and-gun, however, this one is a straight beat-em-up in Ninja Turtles style.
It sort of liberally cribs ideas from other beat-em-up legends; the main characters turn into beasts a la Altered Beast, there's some little cat/lemur/idunnowhat thing that runs around with a bag that you have to whack to get power-ups a la Golden Axe, the map between levels looks suspiciously like that of Final Fight, etc.
However, it looks great, plays very smoothly, and there's a fairly rockin' Kukeiha Club soundtrack that sounds like outtakes from Dracula X and Symphony of the Night. As such, I'd have to give it the thumbs up even though it's kind of short and definitely doesn't derivate much from the tired old beat-em-up pattern. Golden Age of Konami man, what can I say.
* Gameplay Video