This was a really creative idea. I loved the mechanic of the editor. Especially in a fast paced-game. The jump controls felt REALLY good. Good air control. Nice springiness. Gravity was really good. I'm jealous of your jump controls.
I found the placement to be a bit odd for myself, as I tried to place platforms 2 wide and sometimes they would overlap or be a space apart. Although come to think of it I never tried the click and drag method.
Overall really solid concept.