Worse visual quality with OpenGL 2
The game seems to have some visual issues when being compiled with gl2 instead of gl1. I can notice a worse font rendering in them menus and also a worse mouse shadow (seems to be rasterized with a lower resolution). During the race I've considered issues with the horizon.
The game is compiled on Ubuntu 20.04 with the gl2 switch. I can remember that this didn't happen some years ago.
Both issues are related to gamma. I fixed the font and cursor shadow, but not the horizon. I don't know how to easily fix the gamma for the horizon, because I've noticed gamma is applied twice there. If I do a condition for this, most of the HUD has wrong gamma applied.
If you disable gamma (set "Brightness" to "1" in game settings), the horizon will be correct.