I just realized that there's a pretty crippling bug which stops the double-jump from working if the player jumps from the edge of the platform. I already know exactly what is causing it and it only requires altering about 2 lines of code, so I will do this tomorrow sometime.
Some other fixes coming soon also, as well as some unlockable modifier/mutation options and general tweaks, although these will probably take a bit longer. Thanks.
Double jump bugfix has been posted. Enjoy and thanks for the downloads!