Image credit: Walyou
1. Every other character in the game is focused on getting Mario. They become more hostile and determined the longer he is in the dream and the more he does to effect the environment.
2. The “levels” use similar architectural traits and contain constructions that seem to extend the time he spends getting from a to be.
3. Mario levels are like a maze. It’s as though they’ve been designed to keep him around for longer.
4. The music changes in pace (gets slower) the deeper Mario goes.
5. How an Italian plumber finds himself in a mushroom infested world is never really explained. How that world changes from level to level is also not explained.
6. When Mario dies he doesn’t die in real life. In fact, his dream continues. If he runs out of lives he continues from a previous level.
7. He often experiences a falling sensation.