The Ghostrunner demo is beautiful – and ray tracing adds to the spectacle

Ray traced cyberpunk ninjas – four words that sum up Ghostrunner, a new Unreal Engine 4-powered speed running assassination game that melds the kind of 3D traversal we saw in Mirror’s Edge with an aesthetic heavily inspired by Blade Runner. It’s all night time, glass, metal and rain – the perfect scenario to get the most out of hardware accelerated ray tracing – and the perfect setting to look into the RT features delivered by the Epic middleware. First impressions? It’s very promising, but also in its early days, with lots of tuning and optimisation required.

The Ghostrunner demo itself is essentially an extended tutorial that guides you through the play mechanics before settings you loose on some ‘content’. You’ll learn to run, jump, wall-run, boost and to laser-lasso to grapple points. You’ll also learn focus: a Matrix-inspired bullet time mechanic that allows you to dodge incoming fire before unleashing katana justice on anyone who crosses your path. It’s fast, it’s brutal, it’s relentless – and it’s fun.

In terms of play, what sets Ghostrunner apart from Mirror’s Edge is that the mechanics are set up to incorporate kills into your speed run, as opposed to breaking the flow and slowing you down. It’s also a game that encourages experimentation through the use of a rapid restart mechanic. Death is an ever-present companion in Ghostrunner but with one button press you’re instantly back in the action with no loading.

But it’s the real-time hardware accelerated ray tracing features I was really interested in checking out. This is the second public release of Unreal Engine 4 RT content we’re aware of (the first being Deliver Us The Moon from Keoken Interactive and Wired Productions) and it’s flagged as being experimental in nature. Turning on the RTX features enables three features: ray traced shadows, ambient occlusion and reflections. Suffice to say that the performance cost is high: in our tests, frame-rates are generally reduced by 64 per cent, but it the RT features are experimental and there are numerous routes forward for the developer to improve matters.

I can say this with some degree of confidence having taken a more detailed looked under the hood. The Universal Unreal Engine 4 Unlocker is a fascinating tool that opens up the command console within UE4 titles, and from there we’re able to individual enable RT components, adjust their parameters and measure performance. For example, RT shadows adds shade to smaller objects, increases shadow resolution significantly and adds contact hardening (the closer to the object, the more defined the shadow – the further away, the more diffuse). It’s often a ‘light’ RT feature but here it can still have an impact of between 39 to 63 per cent to performance. Ambient occlusion sits on top of the game’s SSAO and has a flatter cost – between 28 to 34 percent.