Crashphalt Dev Finds Steam Game Is Fueling Undertale Multiplayer Mod

RetroSpecter noticed the anomaly only after Crashphalt, the indie platformer listed on Steam, had racked up more than 500 reviews despite spending years almost untouched. The game launched in 2018 and had barely collected about a dozen reviews in its first four years, making the latest surge look even stranger — especially because most of the new comments were about Undertale, not Crashphalt.

The reason turned out to be Undertale Together, a fan-made Undertale multiplayer mod that normally supports only local co-op. A YouTube tutorial showed a workaround for playing it online by copying Crashphalt install files into a modded Undertale folder and renaming the Undertale executable to Crashphalt.exe, which makes Steam think it is RetroSpecter's game and enables Remote Play multiplayer.

That trick had a measurable effect on Crashphalt's numbers. Between November and December 2022, its peak daily player count jumped from 6 to 107, which SteamDB data puts at a roughly 1683% increase. The timing also lines up with the December 2, 2022 upload date of the tutorial video.

RetroSpecter said the discovery left him baffled:

He later added that Crashphalt was "just the lucky game chosen for the honor."

The developer did not sound angry about the attention. Instead, he said it was cool that the game had found a way to affect the community, even in a small way, and help friends play together. There was also another spike in Crashphalt activity in June 2025, which coincided with Deltarune's full paid launch on Steam.

Does this kind of accidental boost make neglected games more likely to get a second life?