- Cut Song: When allegations of plagiarism for the "Metal Gear Solid Main Theme" began to surface during the game's production, the game's theme song, "Show Time," which originally included the "Metal Gear Solid Main Theme", was re-edited so that it didn't. Sadly, this was not a temporary change, and the song has never surfaced again, even in the 20th anniversary soundtrack collection (also, this is the only game with Metal Gear Solid in the title that doesn't have Metal Gear Solid's game over music at all, including Ghost Babel, but this is generally viewed as less significant by fans).
- Mid-Development Genre Shift: Portable Ops originally began development as a competitive multiplayer shooter similar to the online multiplayer mode in Metal Gear Solid 3: Subsistence before it was made into a story-based Metal Gear Solid game.
- The Other Darrin: The CIA Director was "voiced" by Paul Collins in Metal Gear Solid 3 and voiced by Jesse Corti here. Somewhat justified, though, as while Collins might have voiced the CIA Director, he didn't actually have any lines, as he only had a minor grunt of disgust when Naked Snake refused to shake his hand.
- Recycled Script: Grab Metal Gear Solid. Replace Solid Snake with Naked Snake, Liquid Snake with Gene, FOXHOUND with FOX, Deepthroat with Ghost, and some other changes and you'll get the script of Portable Ops.
Trivia / Metal Gear Solid: Portable Ops