- Dueling Games: Dig Dug was also released in 1982.
- Follow the Leader: Mr. Do!'s Castle is a variation of Space Panic. Justified as both games were made by Universal.
- Most Wonderful Sound: That tingling noise made by the diamond.
- Sequel Difficulty Spike: Castle, Wild Ride, and Run Run sport a much higher difficulty than the original. The more restricted and open fields of Castle and Run Run respectively give the enemies a higher chance to ambush or corner you, while the alternate win conditions besides killing the enemies are much harder to accomplish.
- Serial Numbers Filed Off: The BBC Micro port is titled "Mr. Ee!" but otherwise plays very much the same.
- Suspiciously Similar Song: When the game was released on the Super NES, this was done to the previously mentioned Astro Boy theme.
- What Do You Mean, It Wasn't Made on Drugs?: You're a clown that has adventures underground, in a castle, or an amusement park, attacking by throwing orbs or using a hammer, and avoiding a wide array of shapeshifting monsters... and roller coasters.
YMMV / Mr. Do!