Looks good! It's more condensed than the NES game, partly because of Pico 8 limitations. So it gets to the harder levels a bit quicker, but beating it is probably easier.
It is possible to do multi-cart P8 games to work around the limitations. Sort of like overlays, or even bank switching ;-) We've been looking for a game that implements that we can work with to also support in Argon. We're using fake08 with some extra pre-processing as the core.
True. I wanted to stay within the limitations, because I felt it was sort of the point of making a Pico 8 game. Some of the mechanics make a return in the megadrive game though.