Controversy of Active Shooter
Active Shooter was going to be a first person shooter available on Valve's Steam online store, created by indie developer ACID. On May 29, 2018, days before the scheduled release date of June 6, 2018, the game was pulled from Steam along with the developer's other games.
There is also an article for the game itself.
Despite the developer being very obscure before this, Active Shooter gained major attention from gaming websites and communities because one game mode would let the Steam users play as a shooter perpetuating a massacre at a high school. Even an online petition was created pleading to Valve to ban the game and it was signed by more than 180,000 people. Upon banning the developer, however, Valve alleged that it was done because he had already have been banned previously, because of toxic behavior as a developer:
“This developer and publisher is, in fact, a person calling himself Ata Berdiyev, who had previously been removed last fall when he was operating as ‘[bc]Interactive’ and ‘Elusive Team’, (..) a history of customer abuse, publishing copyrighted material, and user review manipulation. (...) We are not going to do business with people who act like this towards our customers or Valve, (...)”
Valve made this statement for the website Kotaku, and as Kotaku's writer pointed out, this means that Valve is claiming that they did not ban the developer from Steam because of Active Shooter's content. The developer was actually a sockpuppet account of a previously banned developer, who had already sneaked back into the store and had several games released yet Valve didn't bother to do anything about a banned developer blatantly circumventing a ban. It is also worth noting that the only reason Valve realized the developer was a previously banned user was because Steam users were the ones who found out and reported it, yet again demonstrating Valve's total lack of moderation for Steam.
Apparently, the game's concept was ripped-off by Berdiyev from a video game project made by the US Army for school teachers as a training for such situations. The game may have also been inspired by a controversial Half-Life 2 mod named School Shooter: North American Tour 2012, which was pulled from Mod DB and cancelled.
Eventually, the game was renamed for Standoff and released at the developer's website.
In June 2018, PayPal closed the ACID account, citing that the game violated their Acceptable Use Policy with IndieGogo removed the title from their service at the same time. With the petition from Sandy Hook Promise, Bluehost also closed down the ACID's development website for the game.