is "maddeningly replaying the first level of the game that inspired your project over and over to reverse engineer the mechanics" like, a normal part of game development or
Yeah, actually!
I don't know how much this plays to what you're saying but if I'm working on something like, say, Sonic inspired, I'll play the game again, and again, and again, and again - sometimes even recording footage, just to take it, frame by frame, slow motion, even - to really study everything down to the pixels. Animations, physics, all of that - even if you don't plan on going super far with something, it's a great study