Pretty good platformer, the controls need a bit of working out. In reply to the person below, you cannot double jump (at least in the amount I played). You can fall off a ledge (without jumping) and then jump mid-air. I see how you've tried to encourage the player to do it in that tutorial, but it still wasn't very intuitive. Maybe it needed a bit more explaining.
The jump arc is a bit weird. it's really high, and you don't have a lot of control over it. You can slightly adjust the height of your jump with short taps, but only slightly and the shortest tap I could do was a still a bit too high of a jump. The fact the x velocity remains as it is when you let go of the keys removes a bit of control. Jumping took a bit of getting used to.
Music is nice, and so are the minimalist pixel graphics.
Only problem is perhaps a bit of refinement of the platformer controls and tutorial, just thought I'd try putting what others have said into actual constructive advice.
Other than that, it was a pretty good platformer after I got used to everything. Later levels introduce new interesting mechanics. Good job.