This is a short info message for developers who would recognize and search for this issue. Higher percentage of WebGL games made in Unity became non-playable after release of Firefox version 63. This version is available since October 23. The problem relates all major opearting systems. Example of affected games: https://www.gamearter.com/game/insurgents-2-mp (Multiplayer FPS) https://www.gamearter.com/game/fighter-aircraft-pilot (Singleplayer aircraft) Steps to reproduce: Install FF ver 63, 64-bit. (Latest version currently). If the problem does not occur itself, try cause heavy particle (like fire or explosion - eg hit a ground with an airplane in the game at second link). Problem fixing: This problem is not available in Firefox ver 64 (beta) in day of writing. Version 63 was reported to Firefox via bugzilla. https://bugzilla.mozilla.org/show_bug.cgi?id=1502748 Feel free to share own experience or expanding informations in the comments.