Although short, this demo shows so much love and care. The environments, character designs, and even UI choices are brilliant. You managed to mix the best parts of Paper Mario with the best parts of Mother 3.
One note I had regarding the battle system was that it lost a bit of it's unique Mother charm when transitioning to Paper. The lack of a scrolling HP bar is saddening because it makes the climatic final attack the Mecha Drago does before being defeated impossible/hard to implement. That said, the additions to the combat system are very intuitive and fun. I especially liked how you handled the luck-based Power Smash.
Another minor complaint I have is with the audio balancing. I felt like certain SFX, like the Mecha Draco roar, were way too loud. The background music also felt overpowering, but maybe thats just me.
I'd love for you to turn this demo into a fully fledged fan-game, but I also understand the reasons why that'd be hard. For now, this stands out as an exceptional experience. I will definitely be sharing it with all my friends.