This was pretty nice and fun, especially for a first game. I played it all the way through to the end. I think the difficulty picked up pretty nicely and the platforming was challenging enough to keep me engaged the whole way through.
A couple things I think could be improved:
Music and sound effects would help a lot in making the game feel more alive.
I didn't actually realize that dashes worked in the air until I had to use it in a narrow hallway, which could be a me issue but I felt it was worth mentioning. (Also, I think Z and Right Shift might be a more comfortable control than 1 and 9 for a lot of people.)
The most important one for me: The character drops like a stone if you're not holding the jump button. Towards the end it became less of an issue as I held my jumps, but at the beginning it was really disorienting. There was also an instance where I was getting an apple from a ledge and I couldn't see below me, but the character dropped so fast that I couldn't even begin to correct the movement in time.
But overall I think you did a good job with this and I think you have a lot of potential. Hope this review helped!