Move with arrows or WASD. You can pass through blue platforms. If you're on one, press the down key (or "S") to fall over. Press 0 for level editor. In the level editor, keys 1, 2, 3, 4, 5, 6, and 9 for selecting tiles. Put a life over a mystery box to put it in. In a mystery box, when there is nothing, a coin appears. Put a Piranha Plant on top of a pipe to put it in. Press E when your mouse is over a tile to select it for the level edition. Press 0 to go back to the playing mode. Press Q to toggle auto-correct. When you are in the edition mode, you can press "R" to reset the level (answer the questions to make sure it's not a mistake and to give the correct value to the width and the height of your level), or you can also press "L" to choose one of your levels, as you can save more than one. Have fun!
Art from the original mario game Play here for best experience: https://turbowarp.org/542098024?interpolate