Nightdive Studios have been working on their remake of System Shock for a while now, and had initially chosen the Unity engine as the technology platform for it. However, it would seem that they recently made the decision to switch to using Unreal:

Nightdive Studios will be giving System Shock a “faithful reboot”, by sacking Unity for Unreal Engine 4. A risky endeavor for sure, but game director Jason Fader assures us that they’ve “mitigated [the] risk by switching early”.

The developer had a wonderfully successful kickstarter campaign last year, and the decision to switch engines was reportedly contemplated in August 2016. The motive, to maximize performance on consoles.

“After listening to everyone during the Kickstarter campaign, it became clear that console support was very important to a lot of you. We took a hard look at what Unity could do on consoles, and what we wanted to achieve for both visual quality and performance. While Unity is a great engine, it was clear that we needed to use an engine that fit our project goals more closely.”

A preview constructed from pre-alpha in-game footage has also been released, showcasing just what Nightdive have been able to do using Unreal:

https://www.youtube.com/watch?v=gv_i6I5N4o8

I get the feeling that the enemies in the video are placeholders, but apart from them it all looks fantastic.