Nice game! I was able to complete almost 4 levels. Gave up at the end haha. I had only one thing to suggest. Maybe in such platformer games you can keep thee camera following the player but if we could see where we are landing more often then it would be real great. Would give a feeling of a precision platformer. Overall really nice job for your first game. Also the jump function you might have put a timer on it. I could  double jump in air if i pressed jump after letting the character jump fully the first time then during the descent I was able to jump again. I don't know whether it was intended or not just thought of mentioning once 

Overall quite a fun and  challenging game. Art was real nice and the music too was engaging.