Honestly, I think he’s right on that one. No tinkering means no tinkering, selecting a proton version to force to use the windows version of the game and passing command arguments is tinkering. That is the difference between gold and platinum in protondb, gold means it works with tinkering while platinum means works oob. L4D2 is marked as Gold, so protondb agrees that some tinkering is required, his complaint that a Valve game in a platform Valve is pushing should work without tinkering is perfectly valid.