Yeah, after a play through this, my first thought was it seeming pretty untested. There's a plenty of glitches. Mainly about HDMA:
this patch will fix most of them. Also, in the third level: having a goal sprite (by the way you really should fix the sphere graphics) in a level with layer 3 is not very fun, the layer 3 won't disappear as it should, and I even got stuck because of it once.
I could also find many spots where we can gets stuck. The latter not only due to the lack of reset doors, but also because many of your puzzles were rather misleading and confusing, and many times I didn't know what to do with that one item.
As for the aesthetics, well, I see what you were trying to do there, but I think the decorations were quite out of place. The weakest point of it is how difficult it is to differ what's decoration and what's actually usable. The difference between both kind of tiles is made by a really slightly different palette, the difference is almost unnoticeable.
Overall, I didn't enjoy this demo as much as I was expecting. The badly-explained puzzles were rather annoying to me. The third and fifth levels were the most annoying of all, because I was forced to fight against the water flow. Watch those out, and remember to
always test your levels as you go progressing in them.
You seem to be a potential hacker. You just need to focuse more on level design and make sure the players of your levels are going to have fun. Good luck with this project!
It's easily the best thing I've done
So why the empty numb?