Sonic the Hedgehog cheats: level select, debug mode and all six Chaos Emeralds

The 1991 codes still work, because this is the 1991 cartridge. Here is exactly what to press — and which keys the A button and Start actually are in the browser.

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The level select code (and how to press it here)

This is the one everybody wants, and it still works — the ROM on this site is the same 1991 cartridge the code was written for.

1. Let the game reach the title screen, with Sonic tapping his foot. Do not press Start.
2. Press Up, Down, Left, Right. If it worked you hear a ring chime.
3. Now hold the A button and press Start.

On a keyboard here, A is S and Start is Enter — so hold S and tap Enter. You land on a screen listing every zone and act, plus a sound test. Highlight a stage, press Start, and you are in it.

Two things go wrong for people. The first is timing: the chime has to play, and if you fumble the four directions you have to leave the title screen and come back. The second is the letter: A on a Mega Drive pad is not the leftmost key on your keyboard. In this emulator the three face buttons map to S (A), X (B) and Z (C). All three jump in-game, which is why almost nobody notices the difference until a code asks for one specifically.

Debug mode: place objects, fly through walls

Debug mode is the level-select code's stranger sibling, and it needs the level select screen open first.

1. Open level select with the code above.
2. Using the sound test at the bottom, play these four in order: 19, 65, 09, 17.
3. Highlight Green Hill Zone Act 1, hold A and press Start.

In the level, press B to become a placeable object — you turn into an item marker that moves freely through scenery. A cycles through the objects you can become, and C drops one into the level. Press B again to return to being Sonic, wherever you have floated to.

It is the fastest way to see the parts of the game you never reach: the tops of Star Light Zone, the sealed rooms in Scrap Brain, what is actually underneath Labyrinth. It is also the fastest way to soft-lock a run, so use it on a throwaway game rather than one you care about.

All six Chaos Emeralds — there is no shortcut

Sonic 1 has six Chaos Emeralds, not seven. The seventh arrived in Sonic 2. There is no code that hands them to you; every one is won in a Special Stage, and you only reach a Special Stage one way:

1. Finish Act 1 or Act 2 of any zone holding 50 rings or more.
2. A giant ring appears above the goal post. Jump into it before it disappears.
3. You drop into a rotating maze. Steer to the emerald, avoid the GOAL blocks, and get out with it.

Practical notes that matter more than they sound. Act 3 has no goal post — it ends with Robotnik — so every zone gives you exactly two chances, twelve in the whole game for six emeralds. Getting hit anywhere near the end of an act is what actually costs people the run: you scatter your rings, and 50 is suddenly 6. And the maze rotates rather than the screen, so the safest habit is to stop reacting to the wall coming at you and start reading where the level will be a second from now.

Collect all six and the ending changes: instead of Robotnik taunting you with the emeralds he took, you get the good ending. That is the entire reward, and it is the reason people still replay a thirty-year-old platformer.

The other codes worth knowing

• Sound test / jukebox. The level select screen doubles as a music player for Masato Nakamura's soundtrack. Enter the level select code and just leave it there.
• Frame-by-frame slow motion. With debug mode active, pause the game and press B to advance one frame at a time — the only way to actually see what killed you.
• Save states. Not a cheat from 1991, but the most useful one on this page: the cartridge could not save at all. The emulator menu under the game does Save State and Load State, which is how you keep a six-emerald run alive across a lunch break.

Cheats that do not exist

A lot of what circulates for this game is invented. There is no level select variant that also grants invincibility, no code for infinite lives, no button combination that gives you the emeralds without the Special Stages, and no Super Sonic in Sonic 1 — he debuts in Sonic 2. If a list promises those, it is copying another list rather than the cartridge.

Everything above was entered on the ROM running on this page, in this emulator, with those exact keys. If a code does not take, it is nearly always the title-screen timing or the wrong key for A — go back and try the four directions more slowly.