What just happened? For the last several decades, the only way to play the unreleased sequel to Atari's Marble Madness was through a handful of prototype arcade cabinets. That all changed this week with the unexpected leak of the Marble Madness II ROM and nobody seems to know why.

As the story goes, Atari developed a sequel to Marble Madness and created a handful of prototypes for internal focus group testing in the early 90s. Feedback wasn't all that hot, however, and Atari reportedly blamed it on the game's trackball controls. Another prototype was made with an updated control scheme that replaced the trackball with a joystick and accelerator button but it didn't fare much better.

Rather than try a third time, Atari scrapped the game and moved on to another project. It was thought that maybe a dozen or fewer prototype game boards survived.

Recently, an emulator-ready ROM of Marble Madness II started circulating on the Internet. As Ars Technica highlights, it's unclear who is responsible for the dump but longtime MAME contributor David Haywood has a theory.

"I think the most likely explanation is the simplest: a PCB turned up, the owner dumped the ROM data from it and put it on The Internet Archive, not wanting the attention it would bring with a more public announcement," Haywood said.

The leaked ROM is of the second, trackball-free version of the game. Its release is significant from a historical perspective but that doesn't make it a good game.

"Marble Madness II is a classic example of [when] a beautiful game is created and the sequel completely forgets why the original was great," said Jason Scott with the Internet Archive. "I am excited that this long-anticipated game is out in the wild, because people can realize how uninteresting the game is and move on."

"I think Marble Madness captured a lot of imaginations, and whether the sequel was worthy of it or not, it's hard not to be compelled by the idea of it," added Frank Cifaldi, founder of the Video Game History Foundation. "We all love a good 'what if' story, [and] unreleased games like this are the closest we get to peeking into alternate realities."

Image credit: The Arcade Hunters