Many games are held together by duct tape. Looking behind the curtain can be eye-opening.

One of the things I like about speedrunning is how they're able to exploit code issues for their own gain. While there's certainly something engaging about watching a run that is just optimal execution, there's also something engaging about watching a run where the game goes completely off the rails on account of glitches. Many of the modern 3D Sonic games are like this, with tons of unintentional physics tricks and abuse of out-of-bounds areas.

Speedrunning would be far less interesting to me if every game were thoroughly polished and had clean, perfect codebases that worked entirely as intended.