Really not sure what this is. The game boots up as an American copy- but I haven't played much to see if there are differences.

Could this be a proto or a frankinstien cart?

Looks like a proto to me

proto seems likely. what's the other side of the board look like? the nolans had a mega man 2 (?) proto like this.

Prototype seems likely. What are the differences between famicom and NES elevator action?

The only difference I saw looking on YouTube between the Nes and Famicom was the text at the bottom of the title screen.

Looks like a prototype to my untrained eye.

Lots of em have no differences from retail I believe. I haven't played either version thoroughly, but from quick sessions my Robin Hood proto seems to be no different.

Yeah, finding prototypes which are 'same as' or 'very nearly the same as' final aren't uncommon. It'd still be worth dumping it, though, since there could certainly be changes to the code that might not be immediately visible during a regular playthrough.

Prototype, zero doubt.

Thanks for posting this. Found another one just like yours last night.

Where did you get it from?
 

I found it on OfferUp last night. I remembered reading this post a while back,so I knew what it was immediately.

Sweet find!