Delivering a Top-Tier PC Port for Returnal
Having provided cross-discipline support on the original PS5 release of Returnal, Keywords’ Climax Studios was brought back by Sony to port it to PC.
At the time, a number of recent major PC releases had been plagued by poor performance, compatibility issues, lack of PC-specific functionality and lacklustre player experience, and audience-confidence was low. Climax’s aim was to deliver a rock-solid port that would offer fully optimised performance, best-in-class support for PC technology, and a range of PC-specific functionality – one that ultimately would prove the doubters wrong.
PC games, particularly those developed using Unreal Engine 4, have historically often been marred by poor performance and gameplay stutters. Due to a number of sub-par ports and releases over the years, PC gamers are acutely sensitive to performance issues.
So the challenges involved in porting Returnal were clear: a fast action twitch shooter that needed a rock solid frame-rate and seamless gameplay to deliver a high-quality playing experience. It was a title that pushed even the PS5 hardware to its limits and included several bespoke graphics systems that had been built without consideration of differing hardware capabilities.
Performance: due to the nature of the game, with the port of Returnal it was essential to maintain a solid 60fps and to avoid any issues with micro-stutters, frame-lag or latency.
Hardware Support: a wide range of PC hardware would have to be supported, from a relatively low-end minimum spec all the way up to the latest GPU and CPUs, and the UX would have to be adjusted appropriately. In addition we needed to support a wide range of peripherals such as ultra-widescreen monitors, surround sound technologies and various controller options.
Custom Features: a number of PC-specific features were required, including a top-tier benchmark mode and support for the latest vendor-specific graphics technologies.
Performance was the central challenge from the start, and throughout the project Climax undertook a constant cycle of profiling and optimisation to ensure all targets were hit.
Key measures included:
- Implementation of scalable, PC-specific versions of the original game’s custom render systems, allowing essential effects to function across a range of PC hardware. As well as programming work, this also involved the reauthoring of assets.
- Overhauling systems in key areas where PC hardware struggled in comparison to the PS5, in particular loading and streaming systems that previously relied on the PS5’s rapid SSD system.
- A systematic approach to building a full set of PSO data to prevent shader cache misses, a common cause of micro-stutters in PC releases.
To ensure a fully optimised user experience, a rework plan was developed for most of the game’s UI elements based on close scrutiny of the entire game on a wide range of monitor resolutions and aspect ratios.
For the benchmark mode we focused on collecting the most detailed system profiling information possible, replicating real game-stress situations and utilising actual game system code paths tweaked to perform repeatably.
Climax had been instrumental in the original development process, and our ambition in porting Returnal was to deliver a PC game that would honour the PS5 version and provide premium playing experiences for a new audience of gamers. The technical challenges were extensive, but in the end feedback from press and users alike was overwhelmingly positive. The release achieved a Metacritic score that was in parity with the original release, an almost unheard-of feat for a PC port, and garnered glowing reviews across the major gaming press.