I couldn't do that first jump.
Viewing post in Of the Sky jam comments
In order not to forget it, it has to register in the first place. I'd just been taught to jump, so I thought the puzzle was going to test my jumping ability. Double-jumping didn't work, neither did jumps from different places or running jumps. I didn't even realise there was a concept of a glide jump. Sadly, even the best-planned games will fail upon contact with unobservant players!