The developer of Paranautical Activity, described by its creators as a fast-paced, first-person shooter roguelike, had its game pulled from Valve's Steam service today after its creator posted a death threat to the company's co-founder, Gabe Newell.

Mike Maulbeck, creator of Paranautical Activity, says he released the final version of his PC game on Steam today. When it went live, the game's Steam page indicated that the game was still in Early Access, which Maulbeck believed would "greatly cripple sales and confuse customers."

"This being a project I spent years of my life on, I was very frustrated by this mistake [Valve] made, so I tweeted a series of tweets calling them incompetent that eventually ended in me saying 'I swear I'm gonna fucking kill gabe' or something," Maulbeck said in an email to Polygon. "A statement I obviously didn't mean, but nonetheless was totally unacceptable and driven entirely by the heat of frustration I was feeling at the time."

Maulbeck let loose a series of vitriolic tweets, calling Valve "incompetent" and expressing anger at Steam's "awful fucking monopoly." Maulbeck then allegedly said in a since-deleted tweet, "I am going to kill gabe newell [sic]. He is going to die."

In response, Valve pulled Paranautical Activity from Steam, and according to Maulbeck, contacted him to say it was terminating its relationship with the developer and closing down his Steam admin account. The game no longer appears on the Steam website. In a statement to Polygon, Valve confirmed that the game was pulled as a result of Maulbeck's threat.

"Yes, we have removed the game's sales page and ceased relations with the developer after he threatened to kill one of our employees," said Valve's Doug Lombardi in an email.

Maulbeck says he has attempted to get Valve to reconsider its decision.

"I have since obviously replied to them saying that I didn't mean what I said and pleaded that they consider the monopoly they have on the PC market before totally writing us off," Maulbeck said in an email to Polygon, "but let's be real. If they took the game off the store, they're fuckin sure about their decision. There's probably nothing to be done."

Maulbeck's studio Code Avarice has a history with getting Paranautical Activity on Steam. The developer was denied a publishing deal on Steam Greenlight last year as part of an agreement with Adult Swim.

Paranautical Activity is available through other digital distribution means, like Desura and the Humble Store, but Maulbeck lamented that the game sold 12 copies on non-Steam platforms today.

[Update: Developer Mike Maulbeck announced that he'd step down from his position at Code Avarice: "I feel is it my responsibility to step down from Code Avarice completely so that Steam has no reason to harbor any more ill will towards the company, and maybe even if we can't see Paranautical Activity restored, at least future Code Avarice games may be allowed onto the platform.]