Alright, I'm assuming I'm at the end o the demo, since I can't do anything after going through Kid I_____: Uprising and the following level.
This mod was... sort of decent. You had okay level design, events that worked properly, which is something not many mods have, and it had okay backgrounds.
Alright I'm going to group these bugs and annoyances into categories for easier reading.
In the first main area, you have your background set to scroll fast left, not scroll left layered.
In the place with the floating Hermit Gunsmith, the cloud's transparency makes it get rid of the tiles that you would think should be there.
The same goes for most other things with transparency.
You seem to make no effort to try and make tiles match up at all. This makes your mod look unprofessional.
Many entities have messed up sprites due to you changing their spritesheet. I suggest looking up what framerects are.
Level Design Issues:
At many times you have unreachable chests that you can never get back to again. This doesn't make the player happy.
Having the three chests with WRONG WRONG and WR... IGHT was a horrible idea. It makes the player have to go through all of the tower over again, something that isn't very fun to have to do more than once.
In the place with the floating Hermit Gunsmith, you can still get the Polar Star and initiate the cutscene with Kazuma.
And now there's the issue of story:
It made absolutely no fucking sense. At all.
These are all the suggestions I can think of. Your mod would be a lot better if you followed even at least the aesthetic suggestions.