This game is fantastic. I love the umbrella gliding idea, and it's really fun to ride updrafts. A couple suggestions...
I never look at the meter because it's hard to take my eyes off the player. Maybe make the umbrella fold upwards (as if over-extending) as you float, and when you run out of lift the umbrella snaps full up, and you fall? Or maybe change color as lift drains? It has to be indicated on the player.
Dying and winning are both unpleasant, with all input suddenly frozen. Maybe some animation would make it better?