Really cool, saw this on twitter and couldn't wait to play it.
The circles around the burning barrels in Pwny X Press really helps when travelling at high speed. I don't know if this was intentional but it's a nice touch.
Love the art for all around but Futr stage takes the salt lick.
Yep buying/selling makes sense now. The last change I would recommend is to leave 'press Z to exit' on screen. Especially since the escape key drops you back to the pico shell.