The joy of a Mario game tends to relate to the number, and length, of surprises in a game.
For eg. The Boomerang Suit in Mario Land 3D, or the use of specific level variations (W4.2 in M3DL).
You have 2 unique elements, and what they have in common is they're only used temporarily. Thats the key imo. Short controlled moments of "nostalgia" or surprise.
“When we make some new announcement and if there is no positive initial reaction from the market, I try to think of it as a good sign because that can be interpreted as people reacting to something groundbreaking. ...if the employees were always minding themselves to do whatever the market is requiring at any moment, and if they were always focusing on something we can sell right now for the short term, it would be very limiting. We are trying to think outside the box.” - Satoru Iwata - This is why corporate multinationals will never truly understand, or risk doing, what Nintendo does.
