The fireman's head only ignites once. It never was ignited ever again for the rest of the film. However, the director explains in the commentary that they were on a budget and didn't have enough money for the CGI.
During the fight between Mega Man and Elec Man, crew and camera equipment can be seen reflected in Elec Man's goggles.
"In the scene" "where" Rock and Roll are talking in the kitchen, There is a mirror on a cabinet behind Roll reflecting the boom microphone.