Last month, Valve said it will start removing negative off-topic user reviews from a game’s review score on its digital storefront Steam. On Friday, it put its new policy to work by excluding thousands of reviews for Gearbox Software’s “Borderlands” franchise.

“Review bombing” is when disgruntled fans try to intentionally harm a game’s sales by leaving negative feedback. While it’s sometimes done over unpopular changes to a game, it’s also used to protest unrelated issues.

In this case, Gearbox Software fans are angry over the developer’s decision to sign a limited-time exclusivity deal with the Epic Games Store for the PC version of its upcoming shooter “Borderlands 3.” The title won’t hit other storefronts, like Steam, until April 2020.

Gearbox announced the exclusivity deal on Apr. 3. One day later, “Borderlands 2” received about 1,100 negative reviews focused on the Epic Games Store and not the game itself.

“Was a great game ’til you find out 3 will not be on Steam for half a year,” one user wrote. “Don’t let these companies screw us around like this.”

Gearbox Software CEO Randy Pitchford commented on the review bombing on Friday, saying that misuse of the Steam user review system made him happier with the decision to go with the Epic Games Store. He also pointed out that publisher 2K Games, and not Gearbox, makes all of the decisions about things like platforms, pricing, and exclusivity.

Other “Borderlands” titles were review bombed on Steam as well, which caused Valve to step in and investigate. It ultimately decided to exclude off-topic feedback left between Apr. 3 and Apr. 8 on all of the affected games.

The Epic Games Store has signed a number of timed exclusivity deals with high-profile titles since its launch late last year, including “Tom Clancy’s The Division 2,” “Metro Exodus,” and “The Outer Worlds.”