Pretty simple really, what level/section of a game have you spent the most time on? It could be because you enjoy it or maybe because you can't get past it!
For me, it's probably Emerald Hill Zone from Sonic 2 or the opening level of Streets of Rage, since they're the two games I find myself playing at least once a month.
For me, it's probably Emerald Hill Zone from Sonic 2 or the opening level of Streets of Rage, since they're the two games I find myself playing at least once a month.