that video on mario 64 invisible walls is incredibly impressive but also I feel like the sheer amount of "for some reason"s and "this game is soooo glitchy and buggy" comments in the video are going to do a lot of work disguising the fact that every single one of these optimizations are probably the only reason ANY of that shit runs on the n64 hardware to begin with
experienced gamedevs didn't take these shortcuts for fun, they likely were under signifiant time pressure, under a shifting technical landscape, and trying to optimize for complex collision on a processor whose clock speed is significantly outdone by any post-2007 graphing calculator
the fact that by and large ONLY speedrunners see these issues is frankly a real testament to how well they did
I particularly want to call out the final topic of the video, which is that ground height-sorting in mario 64 is handled by comparing the height of each object's first vertex (in order, which is arbitrary) - which means that in some cases objects can be sorted lower than they should be due to ties or awkward first-vert placement.
I 1000% guarantee you this was a late-in-development optimization addition. They were almost certainly doing some sort of more complex detection and it was eating up too much frame time and so they redesigned it with the two principles that cause the bug in question, which is:
- only compare two vertices' world locations, total, a single math operation
- then abort as soon as the check is successful and don't check any other collision anymore
This smells very strongly of frantic optimization. "what platform is below mario" is a check that has to run every frame and it's almost certain that on maps like Tick Tock Clock there are situations where probably 7-10 possible valid ground planes can be underneath mario at any given time. During dev, not knowing the N64's final specs, you set it up to just be a thorough check that compares every possible landing spot, and suddenly you're a month from release and the game needs to ship in time to be a launch title and mario's ground collision check is taking like 400 ms, your manager is like "just make it run! we'll test for any bugs where the vertices cause weird collision" so you do that and you catch and adjust for anything you notice, and the minor remaining ones get left out.
It's extremely telling, IMO, that ALL the places this bug is an issue are minor props and weird unusual collision cases that are very hard to notice in normal play. There were probably way more at first and then they went through and fixed every reported one by hand. "why didn't they just build a tool" you might think, but they were almost certainly working under significant time constraints and sometimes you just say "good enough" and throw testers at it and then move on to the next bug and the next optimization. This is quintessential game development, and not a bit of it lazy. Shit's hard and time is a real thing.
experienced gamedevs didn't take these shortcuts for fun, they likely were under signifiant time pressure, under a shifting technical landscape, and trying to optimize for complex collision on a processor whose clock speed is significantly outdone by any post-2007 graphing calculator
and the places that weren't shortcuts, or time crunch, well. After you're exposed to the Ubiquitous Internet we now all take for granted, it's hard to really understand just how hard it was to learn how to find anything. Let alone resources to program for platforms or languages that fell outside of the structure of a CS degree. You bought software libraries on floppies. from a store. With many languages, you bought your compiler from the store. Off a shelf. Best Practices was like, four books and a style guide. DooM wasn't open source, quake wasn't open source, hell this was '95ish, open source wasn't even that big of a thing. Debian Stable 1.0 was released in nineteen ninety six. Gentoo was 2002. Mozilla wouldn't release Phoenix until 2002.
consider how much harder finding techniques that aren't in the standard, often techniques that are described with English idiom, would have been if your first language was not English.
Finding good programming resources was virtually impossible. Around that time I remember using Visual Basic and what little Windows API information was (freely) available to do text rendering. I had to guess at so many things to get it working because the information just didn't exist on the web. Maybe it existed in some MSDN documentation for C++ but I didn't have MSVC++ because you had to pay a small fortune to get it. Also, every time I guessed wrong the entire system would bluescreen.
Games are all smoke and mirrors at the best of times and the amount of hacky optimisation things is incredible, as is the amount of complexity because even a simple game has a whole bunch of interlocking systems that constantly interact with each other
but also I have no idea how I'd put together something 15 minutes or less of explaining this with examples and then talking about how they differ or parallel things you do in work applications

This is basically exactly the sentiment I was going to express