Right now dark path is almost empty, you choose a girl to trick into breaking rules, she gets expelled, council gives you more power to avoid more, then you talk with other girls and authorities and she comes back after some time. You will miss bonus memory scenes for unlocking diaries and act2 plays exactly like light path, but with the difference of stripping minigame, which can be finished only in light path, in dark path there are no dialogues, timer instead of tries and the timer makes it impossible to win.