Thank you very much for the advice, i guess to that i need to work 1/2 of the time on the game core than the other is for polishing and debugging.
Yes, level 1 is passable. I had a problem with the decreasing value of the stamina if it was 0.1 higher the game will be too easy and you can fly for ever, so i make it 0.1 lower to make the game harder since it's already hard lol.
Thank you very much for playing, and the advice is to implemented in my next game jam project.