Dumb question, but have you looked at a "complete" list of all SNES games (like this)? If yes, have you watched gameplay of all these games?
Should only take a few hours.
T = O(n) means that there exists a single constant k such that T < kn for all sufficiently large n.
Therefore O(n!2) is not the the same as O(n!), but for example both 10n!, 10000n!, n! + n2 (note the plus) are O(n!).
Another way to think about this: suppose you believe that O(n) and O(n^2) are distinct. Now plug in only numbers that are factorials (2, 6, 24, ...).
Jambalaya