The obvious inspirations from Mario are abundant but that isn't a bad thing! This harkens single back to my SNES days playing Mario World for hours at a time.
Love the simple UI for the demo and I appreciate the accurate control hit boxes when going full screen on your phone. Larger AAA games even have problems with that. Love the simplicity of the artwork on the overhead map and in the levels. It would be nice to have some sort of naming convention showing on the UI however to indicate where you are.
The world map and the levels are accompanied by what I think is the strongest design aspect of your game and that is the soundtrack. Distinct and memorable tunes filled my head and got me humming along.
I only made it to the third level because the difficulty skill is high which is not a negative however some of the hit boxes for the enemies did seem a bit too large and I found myself reaching up to the sky yelling no way more than once!
All in all pretty damn solid with our work to support your pirate twist on a classic Mario formula that does what Mario did best and that is give you a sense of familiarity while playing. Well done I hope you keep up the work on it.