Thanks for the video. I believe I have a solution for you. From the terminal, run the game as follows "./Redshift7.x86_64 -screen-fullscreen 0". The game should start up in a window and the menu should be working as intended. After that, go to the options menu and change the screen resolution to your native desktop resolution. You can then check the fullscreen box to return to fullscreen mode and the menu buttons should continue working. This is apparently an issue with the game engine as you can see here: https://forum.unity.com/threads/fullscreen-gui-bug.338181/page-2 and here: https://forum.unity.com/threads/ui-not-receiving-mouse-events-5-6-0f1.464107/pag.... I was able to reproduce the problem in Debian 9 with Oracle VM and the above solution worked for me. I hope this helps. Thank you for your patience. If you need any info about other command line arguments such as -screen-fullscreen 0, all the information is here: https://docs.unity3d.com/Manual/CommandLineArguments.html