It’s information I’d much rather see in text, and I find the video a bit annoying from a construction standpoint (the speaker has a bad case of Youtube Voice), but it’s really interesting information regardless. This video from Abyssoft contains a deep explanation of MK64’s opponent driving algorithm, and explains that the game selects two rivals for your character on each cup, and that opposing drivers pick one of three paths through the course, and can clip right through walls if needed to continue driving around the circuit.
Explaining the Ways in Which Mario Kart 64 CPUs Cheat (Youtube, 12 minutes)