Move around with the arrow keys. Use "z" to toggle edit mode, and the number keys to select a block type (1 is air). Use "x to use a special command Do not put your levels in the comment section. Unless they are abnormally empty or extremely small, they will not fit.
The "Abilities" list lets you choose what abilities the player can use depending on what gems he has. Double jump is currently the only one enabled. (It's also the only one made so far •ω•)