Here's a list of thing I saw (you probably know most of them already but anyway I don't know what kind of feedbacks you want ^^ ):
I feel like it's a bit slow, but it depends on the type of game it will be, could be cool like this at the end.
I like the thing like, "if you press the down arrow while you jump you can kill the enemies, Otherwise they'll just be stunned" it can be interesting
The pause menu is weird, you can still move (there's still the annimation) so it feels like the game is broken if you press the space bar by accident. But I guess you know that already
You have a little collison polygon problem with enemies I think (see the picture I linked)
By the way the provisional (I guess lol) animation for explosion made me laugh so much, ahah :p
It's nice anyway, looks good! Keep goin :')