The begining of the boss battle theme from The Angry Video Game Nerd: The Video Game is taken directly from a segment of the track: "Porky Means Buisness!" from Earthbound/MOTHER 2.
Earthbound: (sampled segment at 00:53)
AVGN Game:
The same notes play in the beginning of the Porky song. It's not just the 53 seconds section.
If you're gonna say "That's the point where they sampled the part of the song" I'll counter-argument with "they have different instruments in the AVGN track"
On the other hand this was a very good catch. I don't play Earthbound (and I don't have much interest in it) but the AVGN game is something I want to play sometime in the future.