Pick a tile from the left palette, then click or drag on the grid to paint. B paint, E erase, R rectangle fill, I eyedropper, Ctrl+Z/Ctrl+Y undo/redo (50 steps). Pan with the arrow keys or middle-drag. Every level needs exactly one spawn and at least one goal flag. For moving platforms: press where the platform starts, then drag to set how far it travels, and release.
Hit ▶ Play any time. Move with ←→ or AD, jump with Space/Z/↑ (hold longer to jump higher), R restarts, Esc returns to the editor. Stomp on enemies to bop them. Grab coins and gems, tag checkpoints, reach the flag.
The golden rule: you must beat your own level once before you can publish it — that puts the creator cleared stamp on it, so every game on the shelf is proven beatable. Any edit removes the stamp until you clear it again.
Share → Copy code turns your whole level into a text code. Send it to a friend; they hit Import code in the Gallery and play it instantly. No servers, no accounts, no downloads.
Semisolid platforms can be jumped through from below. Springs launch you sky-high. Speed pads turbo-charge your run. Ice is slippery, conveyors push you along. Spikes and lava hurt. Walkers patrol ledges, jumpers hop, flyers swoop between walls. Checkpoints save your progress.