Also the speedruns for that game contain absolutely hilarious mechanics, like throwing the gas grenade to get the door opened faster at UNATCO HQ.

The only game hack I've ever discovered by myself (by being too cowardly to proceed through the main route when I was little, wasting time instead on the unatco base, and mindlessly throwing grenades around).

It doesn't work anymore in modern mods I've played through; they've patched it.