Topic on Talk:Gun
There's one issue with the 60 FPS edited exe: the explosives have much larger blast radius at 60 FPS, causing a couple of missions to essentially have softlocks, at least if played on the "Impossible" difficulty. The first unbeatable mission is actually right near the start of the game (https://streamable.com/wk7nwk), with a couple more later down the line.
I'd recommend keeping the original 30 FPS executable on hand as a fallback for the problematic missions.