Valve has shut down an exploit which allowed games to be released on Steam without any kind of verification.
Aware of the loophole, a coder decided to raise awareness of the weakness by creating their own game to upload - a simulation named Watch Paint Dry.
And it worked - Steam users were aghast on Sunday night when Watch Paint Dry was indeed listed, with a description suggesting it was exactly what it said on the tin - a game where you... watched paint drying.
There were calls for Valve to adjust quality control - not that the game had ever passed Valve's official channels.
Watch Paint Dry's listing is instead the work of Manchester-based coder rubiimeow, who has owned up to the stunt now Valve has closed the loophole.
There's a detailed description online showing the method rubiimeow used, although the impressive parts are how manipulable Valve's approval backend was.
Getting the game set to "released" and making sure other necessary additions were approved - such as the game's Trading Cards - were all achieved by editing various values for the app in Valve's internal database.
"I decided to use the 'untitled app' for an April Fools prank to try and get Valve's attention about the issues," Ruby wrote. "I have been in contact with Valve who have now fixed the vulnerability.
"Something I've definitely learned from doing this is when working with user-generated content that first needs to be approved, do not have 'Review Ready' and 'Reviewed' as two states of existence for the content.
"Or just don't allow users to set the item to 'Released'."
Watch Paint Dry has now been removed from Steam, although Google's cache of its store page is still available.
"Watch paint dry is a sports-puzzle game that evolves around one mysterious cutscene," its listing read. "Bringing in innovative gameplay and requiring high attention to detail, Watch paint dry is a must play for anyone who enjoys mystery ARG-type games.
"Without spoiling much, here's a quick overview of what you can expect: paint drying, a competitive sports-like element, the same scene over and over again, but something changes every time (maybe), a thrilling story (wouldn't recommend for anyone 12 or under)."
And here's a screenshot: