You must explain the buttons and mechanics to the player.
I see in the comments that some players did not realize that it is possible to use wall jumps, you never made that clear to the players.
Make the reset button more 'findable'.
It is impossible to leave the credits screen.
There is an error when you go to the main menu and return to the level at which the character begins to float when jumping. (see here: https://www.youtube.com/watch?v=Zpfzhs6HwDk)
Apart from these little things, the game is cool, I really like music and art, color scheme and all.
Well done.