Each point is one game's rating·dashed lines show each series' overall trend
Games on the chart (9)
 X-COM: UFO Defense | Mar 1, 1994 | Main Game | 85 | 85 | 85 |
 X-COM: Terror From the Deep | Jan 1, 1995 | Main Game | – | 77 | 77 |
 X-COM: Apocalypse | Jun 30, 1997 | Main Game | – | 76 | 76 |
 X-COM: Interceptor | Jun 15, 1998 | Main Game | – | 50 | 50 |
 X-COM: Enforcer | Apr 18, 2001 | Main Game | – | 42 | 42 |
 The Bureau: XCOM Declassified | Aug 6, 2013 | Main Game | 69 | 59 | 64 |
| XCOM 2 | Feb 4, 2016 | Main Game | 85 | 83 | 84 |
 XCOM 2: Deluxe Edition | Feb 4, 2016 | Main Game | 80 | – | 80 |
 XCOM: Chimera Squad | Apr 24, 2020 | Main Game | 78 | 71 | 74 |