Eddie, the robot that gives Mega Man energy tanks, is green on the show, but was red in the games. The character was called Fliptop in the games, but they later started calling him Eddie as well. This was due to his name always being Eddie in the Japanese version, though - NOT because of the TV series.
In one episode, three of Wily's robots pose as a rock band and hypnotize people with music. Spark Man, the leader of this "robot band", was voiced by a real life rock star - Mark McGrath from Sugar Ray.