The graphics look great, the music and sound effects are a nice addition too, but Godot runs really badly in a browser. Playing at the clearly intended resolution, close to what the intro screens are, makes the framerate acceptable in my case.
Personally I think that the extra life leading into a death pit is intended to be a free reset, in case you missed a jump and/or jumped past the first pit.
I was unable to get past the jump on the second level and after 10 lives I just gave up. It seems to be possible, but it's always just ever so slightly out of reach.
It also seemed to be impossible to walk up hills. Not sure if this was intended or not, but in case it wasn't, I believe the move_and_slide function would've been the appropriate solution here. Nice to see other people using Godot, too!