In my early play testing after the submission, I found that the one hit death was a terrible mechanic. This would require you to play the level perfectly which was incredibly difficult. This issue has been dealt with in the upcoming update, due to release in the next couple of days. and by dealt with I mean that you take damage and some knock back when getting hit, but don't have to restart.
I have reworked double jumping after looking at some online sites about creating good platforms. You will literally have two jumps when you are on the ground, enabling you to slide off the edge, fall a little and then still jump twice.
I admit the final level was way to difficult. I myself only beat it once or twice. Thanks for your input! Glad you found this game fun.