Also games have gotten way more complicated since the gameboy colour era. I've coded a basic 2D physics engine from scratch (literally just circles with soft collisions) and its not just enough to set up the vector math correctly. You can literally make a true to real life physics model (as far as the math of infinitely rigid perfect spheres on a perfectly flat plane goes anyway) and have all sorts of problems crop up because computers aren't the universe and order of computation is a bitch.