Thanks for the feedback! I agree that it would have been better to have easier levels to better explain the mechanics. Unfortunately, we didn't have much time to playtest our levels before launch. We'll definitely make sure to keep your advice in mind if we expand the project!
So you need the jet booster power up, but you can save yourself in the situation you describe if you jump at the last second. Kind of like doing a ground pound in Super Mario 64. As far as other speed run tactics go, I found out (on accident) that if you manage to land in the open exit door while falling you don't crash on impact!