- Name's the Same: Dust Man's weapon, Dust Crusher, shares its name with an enemy from Junk Man's stage.
- What Could Have Been:
- Dr. Cossack was named "Dr. Vice" during development, and was originally considered to have influences from America rather than Russia.
- Skull Man's stage was originally something completely different, but the developers were so impressed by his fan-submitted design that they opted to scrap the level and restart it to devote it to him.
Trivia / Mega Man 4