Halo: Campaign Evolved represents massive change for the series: a reboot of sorts, revisiting the original game and modernising it for a new audience. The fact that Microsoft and Halo Studios have ditched exclusivity, promising a day-and-date release for PlayStation players, is controversial enough. But for Digital Foundry, it's all about the technology, and from our vantage point, the use of Unreal Engine 5 is a concern. The reveal had a number of positive aspects, but the footage also highlighted the many technical issues UE5 brings to the party.

It's worth noting that Halo: Campaign Evolved won't please everyone from a conceptual standpoint. For a game as iconic as this, any re-interpretation of the source material is going to lead to some negative feedback - even from the original developers, no less. From our perspective, the work of Halo Studios has much to commend it, and it's certainly closer in style to the spirit of the original than Saber Interactive's Xbox 360 effort, Halo: Combat Evolved Anniversary.

Halo Studios isn't divulging whether the original engine is powering the gameplay code (as seen in Oblivion Remastered and Metal Gear Solid Delta, amongst others), only saying that the new game features "code and systems carried directly over from the original game." The original simulation systems are there for an authentic experience, alongside Unreal Engine 5 for the modernised visuals, but it is here where the game starts to present issues.

The first concerns Unreal Engine 5 artefacts. From a visual perspective, this engine is taxing on all areas of system resources, with Halo Studios intent not just on using all of UE5's top-end features but also running at a target 60 frames per second. From what we're seeing, console resources only go so far.

Native resolution counts in at circa 800p in one shot, but more generally, the lower resolution results in a range of artefacts on UE5's Lumen global illumination solution, resulting in a visible, distracting "boiling effect." This is on top of the aggressive artefacts when upscalers are attempting to reconstruct detail from a low base resolution.

And being Digital Foundry, we have to talk about stuttering problems. Unreal Engine 5 can deliver larger levels and even open worlds, but it does so by streaming in data in an obtrusive manner, or, so-called "traversal stutter." In the 13-minute gameplay demo, there's an action sequence within the Forerunner structure where the player moves forward and backwards through an area of the level, each time hitting an unseen border that causes level data to stream in and out of memory, accompanied by an annoying stutter. This is entirely an issue with Unreal Engine 5 and not an aspect of the game's original engine. In this respect, the game flows less smoothly than the 24-year-old launch version on the OG Xbox.

On the topic of fluidity, it's clear that Halo Studios is targeting 60 frames per second for Halo: Campaign Evolved. In the preview footage at least, it's only achieving that target in more simplistic environments: smooth gameplay indoors gives way to a choppier presentation outdoors. Can this be improved? We'd like to think so, but many UE5 titles currently exhibit similar issues on consoles. In fairness, Halo Studios did release console footage. It could have run the code on an RTX 5090 PC, powering through the performance issues and ramping up the resolution to resolve the lighting issues. Instead, we got an honest look at how the game looks on consoles right now.

Can things improve? Well, there's a couple of ways of looking at it, and that starts with giving Halo Studios the benefit of the doubt. Epic Games is busy at work on addressing issues like traversal stutter in future iterations of UE5. If Halo: Campaign Evolved is supposed to commemorate 25 years of Halo, there's over a year's worth of development time left before we hit that November 15 anniversary. That time could be spent addressing these problems, whether in the current version of Unreal Engine that Halo Studios is using or by migrating to a future version.

Microsoft also has access to The Coalition, one of the few developers to realise the potential of Unreal Engine, and a development resource the platform holder has frequently deployed to improve first-party game performance. In fact, Epic itself has called on The Coalition's services in optimising UE5's showcase demo, The Matrix Awakens.

The alternative perspective is that we're looking at foundational Unreal Engine 5 issues that may not be fixed or can't be fixed by the time the game comes out, and that's concerning. Put simply, Halo Studios has it all to prove, and this is a release it can't afford to get wrong.