The artwork is supreme, i love it so much. all the details, the little sway of his coat, the backgrounds, everything looks really good.
If thats really your first time coding than hats off. the first time i coded i was happy i had text printed on the screen, so this is kind of a huge accomplishment what you did there in my opinion.
The 2 phased layout is a really clever idea for a platformer, i like it. hinting at the other dimension platforms with dashed lines is a good gamedesign choice. So a really good execution for a first game. Super impressive.
I couldnt get past this point cause im too stupid i guess lol :D
I tried like 40 times and then gave up.

A great game you can be really proud of yourself!