Oh, nice find, thanks for sharing!I've been wanting to play this for so long, ever since i saw a video on it on what i believe was a chinese youtube channel. Unfortunately, he would not provide a download link for it.
It's a really amusing and entertaining mish-mash of retro 8-bit / NES content, and for that alone it had a lot of appeal to me.
Unfortunately, it could use some more polishing and balancing i think. It can get boring to wait for the enemies to come back all the way from the border of the screen back to the visible playing area when they are sent flying off, which seems to happen a lot, at least the way i'm playing. It makes the gameplay stall unnecessarily, like you're trying to ride a back but everytime you get some momentum going, the pedalling stops, and then you start back again, over and over (If that analogy makes any sense whatsoever x'D)
It's specially annoying when they are far away outside the visible border of the screen, yet they're launching knives at you from an unreachable distance (Unless you have a gun near-by, i guess, but it is still kind of annoying.)
Nice idea regardless, unfortunately not executed in the best way, i'll probably keep playing it despite its shortcomings and flaws, to see what's next.
Edit: Ok, i picked Kage the ninja and now it's suddenly much more fun due to her long range of attack

however, it seems to make the game a little too less challenging.
Edit2: Ugh...nevermind that...the platforming in stage 2 is sooo frustrating

it definitely needs more polish...for anyone having trouble in this part:
Use the higher jump by pressing down,up and then jump (Really counterintuitive :/ had i not watched the playthrough, i'd probably still be pulling my hair out trying to get through that platforming section lol)