Playing a Metal Slug ROM wasn't just about playing a game; it was about preserving a specific aesthetic. The way Marco Rossi’s hat flies off when he’s hit, the puff of smoke from a rescued prisoner, the grotesque waddle of the alien mummies—these micro-animations were fragile data. ROMs ensured that even as arcades shuttered and original Neo Geo motherboards corroded, the exact digital fingerprint of Metal Slug 2 or Metal Slug X survived.