I've played this short demo and was really astonished by this amazing style. I really like it when people actually try to reproduce a gaming experience from other games, like here: Superstar Saga, which was also one of my favorites (I played it for 4 times in a row already).
The levels aren't flat and boring, instead they're varying and makes it challenging for the player. Although it would be more challenging when you could fall off from the cliffs, but as you stated that this level is mostly oriented on Superstar Saga, where you couldn't fall off, I understand this.
A few downers are, that (because of the disabled "Death on Bottom") there are "invisible" walls which are annoying. All, in all, it's perfect and gets a 4/5 rating from me.