As a programmer, I have zero interest in game development, but I find this dude's deep dives into (mostly) Super Mario World fascinating. As of the past month, he has a couple of newer videos up under the Retro Game Mechanics Explained account, but a few more live at an old account, including the one that first got my attention about glitchy Yoshi. The videos are as advertised: code-level, computer-science-y explanations of what's behind the sorts of games that are primitive enough to be understood at, well, the code level. While a game nowadays might be written in a super-high level visual scripting language, here we have 65c816 assembly code.
RGmechEX has a Patreon page up if you'd like to see more of this kind of thing.