One Of Them is currently under development using 2 different game engines (dim3 and Unity). The dim3 version is a fully playable demo with a stable script base using OpenGL and compiled for i386. An x86_64 version of dim3 is in the works, and while it seems promising, a Unity port is nevertheless being developed. The Unity build is coming along very nicely ideed - there is an all new custom enemy vision system allowing bots to roam the map without any predetermined nodes/checkpoints - see the progress tab for more information.
The full Dim3 demo is available for macOS 10.14 or earlier, and a physics and enemy playground demo of the Unity build is available for macOS 10.14 or later. If you'd like to try it out, or collaborate on the project, or give me a job, get in touch with me