Super Mario Galaxy is about 14 to 15 hours for the main story on average, around 9.5 to 10 hours if you rush, and about 25 hours if you take your time. If you want 100% completion , expect roughly 42 hours on average.

Quick Scoop

  • Main story: about 14.5 hours.
  • Rushed playthrough: about 9.5 hours.
  • Leisurely playthrough: about 25 hours.
  • 100% completion: about 42 hours.

If you want, I can also give you the Mario Galaxy 2 playtime.