I would say the intent of the 60 minutes is to keep games in scope (and also make sure I have enough time to stream them all on my schedule) so yes, the game time is one main play through, not counting other routes. If you manage to have multiple under the time limit that's also fine! I'll add a question to the submission in case other people have the intent of the game being played multiple times for the optimal experience. As long as it all is around 60 minutes (give or take a few) is the main thing.