I'm working on the physics of the jump at the moment, because I also found a bug that would sometime launch the player 10 miles into the air. The colliders also have a fix coming soon

The double jump and dash are both abilities meant to be given to the player later in the game that have been included mainly for testing purposes, I'm also going to be moving the power up that grants the wall climb to a better location in the next build.
(in future builds powerups will be located in rooms you can't get out of without using your new ability)

sticking to walls is meant to be allowed (at the moment), but you should not be able to jump off them, thanks for bringing this to my attention.

Thank you for reporting this bug with the double jump, 

Thanks for the game!