Had the same thing happen with a Doom 2 map I was tweaking, worked fine in GZDoom but the monsters kept getting stuck in weird ways. Threw it in DOSBox and boom, everything acted how it should. Now I always keep a plain boot setup for testing before I mess with any source port stuff.

Yes! This is such a game changer and I wish more people talked about it. I was pulling shots that tasted kind of flat for months and could not figure out why, then I read something about retention in grinders and started weighing the grounds after grinding instead of the beans before. Turns out my old grinder was holding onto like 1.5 to 2 grams every single time, so I was actually brewing less coffee than I thought and my ratio was all off. Once I switched to weighing after, my shots got slower too and the flavor was way more balanced, not sour or bitter anymore. It makes total sense when you think about it because the beans going in are not the same as the grounds coming out. I do the same thing for drip now and my coffee is way more consistent.