How to use this: ➜ Arrow Keys / WASD / Joystick to move in the editor ➜ Keys (0-9, E) to select a block ➜ Click to place a block ➜ Once you're finished, set an end flag to mark the end of your level ➜ Click "Export" to save your level ➜ "m" key to go to the start block The following blocks can be selected: (1) Ground (2) Lava (kills you) (3) Water (you can swim in it) (4) Up Spring (5) Down Spring (6) Saw (kills you) (7) Collectable / Coin (8) Sign (you can put text on it) (9) Checkpoint flag (10) End flag (can only be placed once)
original credit: @TimMcCool