Mortal Kombat 2. Lots of years ago, when i only had the internet at my university, printed out a list of the moves for the arcade. Used to play it on weekends at a seaside arcade, its really a shitty game in single player. The only way to beat it is to exploit the AI because it reads your inputs. We learned the trick that after the 3rd opponent, the AI would just follow you relentlessly, so you duck, jump back, and the AI follows. You could then do whatever attack you liked on it.
So we quickly got to the point where the AI was no challenge, the whole point was showboating. And who better to use...shang tsung. So we quickly learned his full moveset and started doing things like morphing to the other characters at the FINISH HIM and doing their fatalies. If you timed it right you could morph to sub zero, finish the AI, do the first part of his freeze fatality, change back, then quickly morph to scorpion and set fire to the ice. Nice for crowds watching. You could do any move on this, so it would be like see what each fatality did to the iced corpse..they all mostly just glitched it out a bit.
The only down side was kintaro was a huge cheat, the technique to use would be stand infront of him, throw a single punch, then jump kick into him. But mostly the games would take about 20 mins each per credit to run through the entire tower showboating fatalities to the crowd, then die to a boss or beat it.
this sort of stuff:
https://www.youtube.com/watch?v=qNZof-9HquU