Sonic 06.

If you try to play it casually it’s absolutely awful because there’s no guidance on what to do and some of the tasks are awful if you don’t know how to skip them.

But if you watch enough speed runs and LPs of the game you start to figure out why the game breaks, how to do the bad parts, and how to intentionally mess with it. And it’s hilarious to do so. It’s like an unintentional broken sandbox. And the best part is even when you’re not trying to it breaks anyway.