It's so impressive that this is your first completed game, because there are basically two games here!!
You coded a small platformer metroidvania - and then you made a JRPG turn-based combat game too!
The first game was mostly just a series of lock-and-key puzzles, but I love that you found an organic way to implement it using progressively larger jumps and stategically placed speed/height power-ups. I appreciated how the lighting changed when you entered a cave. The music felt like a blend of NES tetris and the Legend of Zelda - there were some really cool triumphant fanfare-type riffs in there.
The second game was fascinating to me. There seemed to be only 1 sequence to beat each enemy, which you needed to puzzle out by referencing the stats in the pocketbook. It was like a puzzle game disguised as a grindy JRPG battle. The game did crash once for me during the third slime battle, but did not impact my overall enjoyment!
There are a few things to work on - the settings menu seems to be broken, the walk cycle it a little clunky, and it would be nice to see an implementation of coyote time for those long jumps -but overall this a MONUMENTAL achievement, Congratulations on your first game and your first full release! This was a joy to play!