🍄 Random Super Mario levels — a new one every time

What it can build

Seven generators take turns, so a run moves between settings the way the original game does rather than staying above ground forever:

Overworld	The classic above-ground run: pipes, blocks, Goombas and Koopas.
Trees	Above ground, built on tree platforms with gaps between them.
Underworld	Brick corridors and coin rooms, the 1-2 setting.
Underwater	Swimming, with Bloopers and Cheep Cheeps instead of ground enemies.
Bridge	Bridge sections over open water, in the style of 2-3.
Sky	Cloud platforms above everything, the bonus-area setting.
Castle	Lava, fire bars and a Bowser at the end.

Levels are always finishable — the generator places floor, platforms and enemies within reach of a normal jump, it does not drop you into something impossible.

If you would rather play the real thing

Every original stage has its own page that starts there: all 32 levels, from World 1-1 to World 8-4. The keys, the hidden ones included, are on controls and cheats, and this page covers running it on a locked-down computer.