Starbreeze will return to being an "engine agnostic" company, despite having acquired the Valhalla engine only two years ago.
Valhalla, which Starbreeze bought in May 2015, was described as being a major step in "[taking] on challenges and opportunities in future game development" and, "of outmost [sic] importance for our aggressive taking of market share." The company said it would be using the engine for the next two project from its main studio, Overkill, including its take on The Walking Dead.
However, that plan has now changed. While Valhalla will remain "the cornerstone of ongoing product development," it will now be using Unreal Engine as "the baseline" for The Walking Dead and its work on Smilegate's Crossfire. "The decision will not impact the release schedule for [Overkill's The Walking Dead]," the company noted.
According to Starbreeze, Valhalla includes technology for "randomization of worlds and dynamically generated gameplay" that are apparently integral to its vision for Overkill's The Walking Dead. With that in mind, it has negotiated with Epic to add Valhalla to the Unreal Engine as a plugin, "for internal use at Starbreeze and for selected publishing partners."