"Super Mario Bros. 3 contains many obvious design lessons that are also present in other games, e.g., the gradual layering of complexity that allows players to master a specific mechanic. What surprised me during my playthrough, though, was how some of these lessons were completely optional.
For example, it’s possible to send a turtle shell skittering in the opposite direction of destructible bricks, or to take the cloud-route and skip certain powerups and interactive objects. Of course these same lessons are repeated multiple times, but they’re not always as heavily hinted.
Personally, this hits a sweet spot for me. The game doesn’t have any forced hand-holding, and it isn’t afraid of the player simply exploring it at his own pace (even if it means circumventing chunks of the experience). This approach also serves to encourage multiple replays, and — back during SMB 3′s initial release — it probably sparked many playground discussions."
Super Mario Bros 3 Level Design Lessons
Super Mario Bros 3 Level Design Lessons @ Significant Bits