Release years by system: 2000 – Neo Geo 2003 – PlayStation 2 2004 – Xbox 2008 – Xbox Live Arcade 2012 – Virtual Console 2012 – iOS/Android 2014 – Windows (Steam) 2014 – Linux, macOS 2015 – PlayStation Network 2017 – Nintendo Switch
Release years by system: 1999 – Neo Geo 2001 – PlayStation 2012 – Virtual Console 2013 – iOS/Android 2014 – Microsoft Windows (Steam) 2017 – Nintendo Switch
Metal Slug Zero Online is an unreleased massively multiplayer online game, part of the Metal Slug series. It was being developed by Dragonfly and WizHands for SNK Playmore and was intended for the South Korean market.[3] There was no word on a Japanese or North American release. The game was on course for a 2009 release, but in the summer of that year, developer Dragonfly suspended development of the game due to their belief that the game could not conform to the trend of current gaming industry.[4]