Versions
| Platform | Title | Region | Notes | Ammo Behaviour | Base Def Elerium |
| unknown | X-COM: Michi Naru Shinryakusha | Japan | source: MobyGames | ||
| Amiga | UFO: Enemy Unknown | Europe | verified by Boba, may also have a CD32 version | ||
| X-COM: UFO Defense | USA | source: MobyGames, may also have a CD32 version | |||
| DOS | UFO: Enemy Unknown | Europe | 1.3, believed to exist | ||
| 1.2, verified by Boba | |||||
| something before 1.2 (1.0? 1.1? both? more?), verified by Boba | Boba remembers it as being in the 500-1500 range | ||||
| X-COM: UFO Defense | USA | 1.4, believed to exist | |||
| Windows | X-COM: UFO Defense Gold Edition | USA | verified by Boba, believed to be identical to Collector's Edition | normal | |
| Playstation | X-COM: Enemy Unknown | Europe | source: MobyGames | ||
| X-COM: UFO Defense | USA | verified by Boba |
"Normal" ammo behaviour means partially-used ammo is lost and unused ammo is retained, regardless of loaded/unloaded or alien/xcom status.