Not even 20 minutes of "demo" - You walk around, that is it. Settings menus also do not work correctly if you dare to combine the use of mouse and keyboard, so must use keyboard only to navigate and apply GFX settings.
On the plus side, the game ran really well at 5160x2160, the defaulted Epic/High mix settings have an additional setting called "Cinematic" which I assume is higher than Epic as it's next along and last. Visually saw little difference. It stayed at 120-144fps on a 4090. You cannot uncap the framerate even though there is an option to, it maxes out at your display refresh rate.
The FOV cannot be changed and by default the FOV is WAY too close to the character and as you move the camera around you feel dizzy fairly quickly.
Also, if you change resolution mid-game, then the framerate tanks to like 40fps which I found, you have to quit the game then go back into it to get framerates back.
Best avoid this and the actual game since I suspect nothing will change in these areas of issue.
No shader comp stutter given this is UE4, but there are some traversal stutter hitching.