The Culling 21:9 Ultrawide Gameplay
A test gameplay demonstrating the 21:9 resolution support offered by The Culling. It offers pretty good support out of the box with a couple of issues, the out of game menu doesn't support 21:9, leaving it bordered (which is at least better than it stretching) and when using a 21:9 resolution the ingame HUD is enlarged compared to using 16:9 resolutions, with no HUD scaling options present at this stage. However, the HUD isn't particularly big enough for it to be intrusive, and if anything might actually help in certain situations, since you can see your health/stamina better at a glance in combat.
The Culling is currently in Early Access on Steam, so any of this could be subject to change, but as long as the developer is aware of the growing 21:9 resolution using PC userbase, things should only improve, or at worst, stay the same.