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First appearance of “Rush” in a Mega Man game

First appearance of “Rush” in a Mega Man game
Who
Mega Man 3
What
First
Where
Not Applicable
When
28 September 1990

Mega Man 3 marked the first appearance of the series' robotic canine sidekick, Rush. It also introduced Mega Man “slide” move, which would go on to save many lives (and help set many speedrunning records) in future games.