A nice platformer, a point that could be improved would be the movement, the problem is that the movement is too rigid, no variation in the jump, almost no acceleration or deceleration, etc...
To solve this problem, one thing would be to give more control to the player, for example to make a jump like mario (varying according to how much you hold the jump button). Or for example implemented a fast fall to break the jump, in short to allow the player to have more control over the physics of the character.
I recommend you to see the Game Maker Toolkit video "Why Does Celeste Feel So Good to Play?" which is a very very good popularization of the subject
But anyway good job :)
I'd appreciate it if you want to try my game too :)
Thanks!