Epic Games is creating a review system for its online store, according to the company’s founder, Tim Sweeney.

“We’re working on a review system for the Epic Games store based on the existing one in the Unreal Engine marketplace,” he recently tweeted. “It will be opt-in by developers. We think this is best because review bombing and other gaming-the-system is a real problem.”

“Review bombing” is when people leave negative user reviews on a video game intentionally to harm its sales and/or popularity. Often the bombing has nothing to do with the game itself. Instead, it’s in response to a perceived slight by developers or publishers.

Deep Silver and 4A Games’ “Metro 2033” franchise recently found itself on the receiving end of a review bombing after it was revealed the digital PC version of “Metro Exodus” is coming exclusively to the Epic Games Store. The upcoming first-person shooter was previously available for preorder on rival storefront Steam. While those preorders will still be honored, irate Steam users began leaving negative reviews on previous entries in the series. Only 28% of the nearly 2,500 reviews for “Metro 2033 Redux” in the last 30 days are positive, according to its product page. Many of the comments specifically mention the Epic Games Store announcement.

“The game is a good one, but that Epic Games was able to buy a year of exclusivity on ‘Exodus’ is disgusting,” one person wrote.

“I honestly cannot recommend this game anymore after the behavior of the developers with this whole mess,” said another Steam user. They then contradicted themselves by adding, “It is still worth playing though.”

“Metro Exodus” was the third high-profile game to jump ship from Steam to Epic Games Store in the last few months. Skybound Games announced in December that future episodes of “Telltale’s The Walking Dead” will publish there. Earlier this month, Ubisoft also announced a deal with Epic for “Tom Clancy’s The Division 2.”

Epic’s revenue model is probably a major reason for the defections. It takes a 12% cut of sales, while Steam takes 20% to 30%.