* FanNickname: Venusians, for the alien race in ''6''. For the longest time they didn't have an official name, and when they did get one it was just "the Invaders", so fans gravitated to a Venus-themed name as a pun based on [[MarsAndVenusGenderContrast their conflict with the Mars people]].
* NoExportForYou: The 3D installment for UsefulNotes/PlayStation2 has not been released in North America.
** Also, from the main series, the Combat School, a mission-based DatingSim.
* PortOverdosed: SNK just loooooooooves re-releasing the original game. It's hard to find a single compilation by them that doesn't include it.
* WhatCouldHaveBeen: Early on, Sophia was considered to play the role of Player 2.
** Many ideas and models were scrapped from the final product, especially in 5. Including a giant turtle-like mecha and the native zapped by the lightning at the beginning as the final boss on a levitating, laser-spitting pillar. See [[http://randomhoohaas.flyingomelette.com/MetalSlug-MissingInAction/MSAction-Main.htm this page]] for all the stuff that people have found from the game files.