Hi, I really like the aesthetics of the game, looks great.
However, the jumping mechanism feels too light, as it has a low gravity. It's a common thing in platformer game tho. But increasing gravity only makes the character can't jump high enough. Here's a quick tips for making a better jump mechanism. The character should have different gravity while jumping and falling. While jumping, apply normal gravity. But when the character is falling ( vertical velocity < 0 ), increase the gravity of the character (double maybe). So the character still able to jump high, but it falls faster. It's not realistic as in real life, but feels good :)