If you're looking for sound effects from the legendary (and notoriously difficult) fan game you can find them across several community archives and resource sites.

: The famous "splat" followed by the game over music is actually a combination of a generic "crunch" sound and the Game Over theme from The Karate Kid on NES.

Used for the intro sequence spoof and the "The Kid's" basic movements. Metroid Series:

: A palette-swapped Zangief boss that uses the roar and sounds of Super Metroid Mecha Birdo & Mike Tyson

: Frequent "Hey!" sound effects found throughout the game often originate from vintage sample CDs like "Voice Spectral," which was widely used in 90s titles like The Legend of Zelda: Ocarina of Time . A Catalog of Nostalgic Theft

: Sound effects like the sudden "warning" siren during the Mecha-Birdo fight (sourced from Ikaruga ) have become universal shorthand for impending doom in internet edits.