44		Space Hulk: Vengeance of the Blood Angels (Windows, 1996)
43		Uprising 2: Lead and Destroy (Windows, 1998)
40		Space Station Oblivion (DOS, 1988)
40		Carrier Command: Gaea Mission (Windows, 2012)

Notes: Games similar to Defcon 5, Games like Defcon 5, Millennium Interactive Ltd., Nova Spring, DOS, Action, Strategy, Tactics, Cyberpunk, Dark Sci-Fi, Sci-Fi, Futuristic, 1st-person, PC, Game Similarities.