Nintendo’s latest retro game console is a handheld game system designed to run just a few games. The Super Mario Bros Game & Watch is a modern take on the original Game & Watch line of single-game handhelds that were released in Japan 40 years ago.

First announced in September, the new model sells for $50 and officially launches today (although it appears to be out of stock). It has a color display and comes with Super Mario Bros pre-loaded, plus two bonus games: Super Mario Bros: The Lost Levels and Game & Watch: Ball.

But soon you may be able to load other games on the little game system, because security researcher Thomas Roth (who goes by stacksmashing) has already found a way to bypass the Game & Watch’s encryption and load custom code. It’s even possible to play DOOM. Sort of.


At this point, DOOM doesn’t run very well (stacksmashing had to remove textures, disable audio, and reduce the screen resolution in order to get the game up and running), but as a proof of concept, it shows that it’s possible to replace the Super Mario Bros game that comes with the Game & Watch with homebrew code. And that opens the door to loading alternate games or other applications.

Given the hardware limitations, you’re probably not going to run Crysis on it anytime soon though.

You can find more details in stacksmashing’s video:

For now it appears that you’ll need some specific tools and specialized expertise to hack the system. The case is held together by Y-style screws, and stacksmashing used a Minipro and SOIC8 clip to connect to the 8Mb flash storage module and dump the firmware to another device so it could be examined.

As described in a series of Tweets earlier this month, stacksmashing’s Game & Watch was actually delivered a day ahead of schedule, and it didn’t take long to find a way to hack the device. So technically the headline of this article is incorrect: the Games & Watch was hacked before day one.

stacksmashing (@ghidraninja)

While the firmware is encrypted, stacksmashing says flash validation is not strong, and it’s possible to alter some code and still boot the system. It’s unclear whether this is something that will eventually make it easy for folks without the same level of expertise to sideload custom code (or maybe even other games) on the Games & Watch. But it does look like Nintendo’s latest retro console is at least somewhat hackable… much like earlier Nintendo retro consoles.

This article was originally published November 13, 2020 and last updated November 24, 2020.

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4 replies on “Nintendo Game & Watch: Super Mario Bros hacked on day one (Yes, it plays DOOM)”

  1. This is great news! Thanks everyone who is hacking stuff like this. This extremely cool new Game & Watch device is perfect for a quick game on the go.

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