I hope I don’t burst a bubble too much, it’s not so much a game dev breakdown, the person is more so reviewing the story and multiple endings you can get (including - spoilers - a false ending that can briefly screw with players the first time).
The gameplay stuff I mentioned is more touched upon in the beginning - they go over how certain game design concepts from separate games are used then clash slightly before it got patched in an update. The rest is mostly about its story and literary references. As well as the fucked up psychological horror mixed with questioning what the Hell is going on - and if you are in Hell.
The crazy in-depth gameplay stuff I mentioned you might not want to use is talked about much later in the video, as those gameplay elements affect what endings you can get - and the lengths you have to go to get them can be kind of crazy.
Edit: checked the video again - at 15:00 (that’s 15 minutes in) the video goes into what was originally an issue but was solved through a patch - the issue was about the game’s inventory system, as - initially - there was the issue that you were limited to 6 slots and there were two very important items that took up slots: the flashlight and the eye accessory that lets you take pictures. There’s more about the gameplay in the rest of the chapter that rant’s in, but that point and afterwards does touch upon how a gameplay mechanic and a design philosophy from different games can clash when not thought through carefully.
There’s also the fact that at one point it mentions how certain items were moved around in the patch. Objects were placed in different areas, probably thinking of the psychology of loot-goblin hoarders that we players can be (I say this as someone who is well aware of what it means to be “Over Encumbered Man/Woman”).
Also, double checked your post about the issues and I just had another brainwave - about speed specifically - remember that transformation thing I mentioned before? Why not add a quick one to turn into a ball of some kind? Basically, at a higher level you unlock an upgrade that allows you to just turn into a rolling ball, sort of like Samus Aran from Metroid. And depending on the fullness of the character, affects how big the ball is. For a bit of fun, I remember there was this comic on DeviantArt back in the olden days - sadly no longer on there - that had this concept called “Bellyfication” - basically, people who were poisoned got turned into round, fat little bellies, and the main protagonist was forced to work with a repeat sex offender (Disclaimer: I don’t think the little Max rabbit wannabe ever went after kids, wasn’t mentioned in the comic - at least I hope not) to try to track down the culprit. It ends with her failing and getting turned, along with the potential suspect being killed.
Granted, I don’t know much about what’s under the hood in programming terms, so I don’t know if it’s as simple as giving the player a simpler, smaller character model or if it’s like the shrinking mod for Fallout New Vegas: your character isn’t smaller, you’re actually in a new, freshly modeled and meshed area.