Might as well make a report if anyone have issues with the game on amd.

Compatibility Report

• Name of the game with compatibility issues: Ancient Cities
• Steam AppID of the game: 667610

System Information

• GPU: R9 380
• Driver/LLVM version: Mesa-git & Mesa 22.0.2
• Kernel version: 5.17.5-arch1-1
• Link to full system information report as Gist: https://gist.github.com/Blisto91/053440951dedddd12fd038f86b5e218c
• Proton version: 7.0-2

I confirm:

• [x] that I haven't found an existing compatibility report for this game.
• [x] that I have checked whether there are updates for my system available.

Symptoms

The game currently doesn't run on amd GPU's using the mesa drivers because it is missing the required GL_AMD_gpu_shader_half_float OpenGL extension.

The workaround until it gets implemented in mesa (see the mesa issue) is to run it through the proprietary OpenGL driver.
For arch derived distros using pacman that would be installing the amdgpu-pro-libgl package and launching with

LD_LIBRARY_PATH="/usr/lib/amdgpu-pro/" %command%

Nvidia should work fine as far as i know without having tested. Or at least be able to launch.
I don't think the game supports intel iGPU's for now even on windows.

Reproduction

Run game on amd gpu with mesa drivers