Yeah a quick PoC is a great idea, but the concept here is "Mortal Kombat" not "Character Selection screen". We all know the Jaguar can play samples, do sprites and animation, this proves nothing with regards to the Jaguar's capabilities to do the target game. I am not knocking him for getting what he has going and having fun doing it, but claiming it's a "start" or PoC is a significant stretch.
To my mind a PoC would show that the parallax was viable with 2 animated characters, not fighting or even controllable, just 2 characters cycling through animations whilst the screen moved around the full extents of the playarea. That would be a better PoC, as it would be doing all the key graphical needs of the game without spending the time needed to add in the controls, AI, game states, score, UI etc etc etc.
There are waaaay too many "I'm making a game, look I have this cool intro/screen/animation" projects, (often followed with box and cart mockups), which then go no where as it turns out "Making games is actually hard".
Not knocking the desire here at all, have at it, make an MK clone for the Jag, do it.