An early version of the cutscene that plays when you beat Roy doesn't use the voice actors from the final game. The voices of the Mario brothers seem to be heavily based on Walker Boone and Tony Rosato's takes on the brothers from the Mario cartoon series airing at around the same time. Oddly enough, this is stored in the data for the final level, not Roy's. There is no known cutscene data.
Contributed by billebobfacts