I really liked this experience!
I think the introduction of ranged enemies on the cliff tops was done really well, especially with the stage that served to show that you can shoot on top of those (I was interested as to why that was the case and then went "ah ha!" on the stage directly afterwards).
I noticed that the cursor disappears if you're in the bottom 30% or so of the screen, but unsure if that's just HTML5 canvas issue stuff or a general issue? Tracking down web export bugs is the worst but it may be an issue with viewport vs resolution size.
The ending reminded me of the ending of Toe Jam & Earl which is one of my favorites, so thanks for that smile!