cyd-ui VS systemshock

For what it's worth, Nightdive did release the source code for the old Mac version and there's currently a cross-platform source port in development based on it: Shockolate.

if you want a source port that looks like the original (none of that KEX engine crap that looks awful), but also has mouse look, you can try shockolate (https://github.com/Interrupt/systemshock). it's not 100% stable though and sometimes crashes. i could not figure out the reason in two full playthroughs, but it was good enough for me if i can avoid the disgusting KEX port.

Though the Ultima Underworld maps were made out of a 2D grid, the rendering was done using texture-mapped polygons - and not just that but they even used dithering for more light variations. While pretty much all objects were rendered as 2D sprites, there were a few 3D polygonal objects too.

Wolf3D has a much more limited renderer - only walls are rendered, no lighting (the shaded side for walls is actually different textures) and the viewport is fixed at the middle of the walls for example. On the other hand Wolf3D was much faster and responsive and had a larger render window than UU.

UU itself was not open sourced, however System Shock 1 which is based on the same engine was[0][1].

[0] https://github.com/NightDive-Studio/shockmac

[1] https://github.com/Interrupt/systemshock

last example, system shock - got open sourced and ported by the community in no time https://github.com/Interrupt/systemshock

I have a more modern source port that works on my Mac (Shockolate), but I still find it clunky to control. Funny how preferences and expectations change over time. I don't remember having an issue with the controls back then (or with Ultima Underworld), but now, it's just really hard for me to get past.

I don't know if you still care, but there's also Shockolate. It's meant to run on modern hardware.

The official KEX Enhanced Edition has had the most work put into it, but Shockolate might be an option if you want to give it a shot.