85		LaserAge (Windows, 1999)
85		Alien Invaders 2000 (Windows, 1999)
85		Space Invaders (Windows, 1999)
84		Invaders From Neptune! (Windows, 2000)
84		Just Shoot The Thing! (Windows, 2000)
84		Ricochet (Windows, 2001)
84		Zak Zapper (Windows, 2000)
83		Out of This World (DOS, 1992)
83		Mars Taxi (Windows, 1997)
83		Avenger (DOS, 1997)
83		Super Stupid Space Invaders (DOS, 1997)
83		N++ (Windows, 2016)
83		CHAMP Galagon (DOS, 1997)
83		CHAMP Invaders (DOS, 1997)
83		Orbsters (Windows, 1997)
83		3D Mars Mission (Windows, 2001)
82		TIE Invaders (DOS, 1996)
82		Natomi Bottle Rockets Extreme (Windows, 2002)
82		Max 2: Counterattack (Windows, 2002)
82		Cybernoid II (Windows, 2002)
82		CHAMP Galaxia (DOS, 1996)
82		Galagatron (Windows, 1996)
82		Cash Invaders (DOS, 2002)
82		Super Mutant Alien Assault (Windows, 2016)
82		Abduction Bit (Windows, 2016)
81		Fighter (Windows, 1995)
81		Invaders 95 (Windows, 1995)
81		Axiom Verge (Windows, 2015)
81		Space Invaders (DOS, 1995)
81		3105 A.D. (Windows, 2003)
80		PC-Fun (DOS, 1985)
80		Gravitar (DOS, 1993)
80		SDI2040 (DOS, 1993)
80		Astrosmash (Windows, 2010)
80		Jetsons: The Computer Game (DOS, 1992)
80		Patriot Command (DOS, 1992)
80		1993 (DOS, 1992)
80		Bandits! (DOS, 1992)
80		Electroman (DOS, 1993)
80		Yars' Revenge (Windows, 2010)
80		Alien Attack (DOS, 1993)
80		PLEBS (DOS, 1989)
80		Horizon Shift (Windows, 2015)
80		Blast Lander (Windows, 2017)
80		Brickquest (Windows, 2006)
80		Pixel Space Battles (Windows, 2017)
80		Totally Tiny Arcade (Windows, 2007)
80		Abstractanoid (Windows, 2017)
80		Out of This World (Windows, 2006)
80		Acky's XP Breakout (Windows, 2004)
80		Invasion (Windows, 2017)
80		Wings 2 (Windows, 2006)
80		Robot Heroes (Windows, 2017)
80		Galaxian (Windows, 2008)
80		Blasturon (Windows, 2008)
80		Capsule Force (Windows, 2015)
80		Super Destronaut DX (Windows, 2018)
80		The Interceptor (DOS, 1993)
80		Explosionade (Windows, 2015)
80		Invaders Possibly from Space (Windows, 2009)
80		1979: Invasion Earth (Windows, 2017)
80		Brickquest 2 (Windows, 2008)
80		Spac3 Invaders Extr3me (Windows, 2018)
80		Love Invaders (Windows, 2005)
80		Space Intruders (DOS, 1993)
80		Space Armada (Windows, 2010)
80		Space Spirals (DOS, 1988)
80		Lunar Take (DOS, 1989)
80		Tommy's Space Goblins (DOS, 1987)
80		Zapshot (DOS, 1986)
80		StarBlade (DOS, 1990)
80		Super Destronaut (Windows, 2016)
80		Clone Invader (DOS, 1989)
80		Plexu: The Time Travellers (DOS, 1990)
80		Space Commanders (DOS, 1983)
80		Tintin on the Moon (DOS, 1989)
80		Star Ship Attack (DOS, 1982)
80		UFO (DOS, 1982)
80		Asteroid Pilot (DOS, 1982)
74		PixelShips (Windows, 2000)
71		One Must Fall 2097 (DOS, 1994)
70		The Eternal Castle (Windows, 2019)
70		Out on a LEM (DOS, 1984)
70		Tommy's Lander (DOS, 1986)
70		Original Journey (Windows, 2017)
70		Space Taxi (Windows, 2004)
70		Computer Space Simulator (Windows, 2005)
70		Gravitar (Windows, 2010)
70		Space Taxi 2 (Windows, 2004)
70		Missile Command (Windows, 2010)
70		Crazy Nick's Software Picks: Roger Wilco's Spaced Out Game Pack (DOS, 1992)
56		DX-Ball 2 (Windows, 1999)
55		3D Astro Blaster (Windows, 1999)
55		Cap'n Crunch's Crunchling Adventure (Windows, 1999)
55		Disney's Arcade Frenzy (Windows, 1999)
55		Isin-Densin Zero (Windows, 1999)
55		Debris (Windows, 1999)
55		Booym (Windows, 1999)
55		U.R.B.A.N The Cyborg Project (DOS, 1999)
55		Digger (DOS, 1999)
55		Dark Moon (DOS, 1999)
55		Solaris 1.0.4. (Windows, 2000)
55		Fire Zone (Windows, 1999)
55		Zeroth Zone (DOS, 1999)
55		Trash Killer (Windows, 1999)
54		Bio Freaks (Windows, 1998)
54		TAGAP 2: The Apocalyptic Game About Penguins 2 (Windows, 2011)
54		Juggernaut Corps: First Assault (Windows, 1998)
54		Galactic Patrol (Windows, 1998)
54		Gunner 3 (Windows, 2000)
54		3D Alien Invasion (Windows, 1998)
54		Operation Spacehog (Windows, 2000)
54		Swarm (Windows, 1998)
54		Gravity Force (Windows, 2000)
54		3D Missile Madness (Windows, 2000)
54		Operation Spacehog (DOS, 2000)
54		Freddy (Windows, 1998)
54		Air-Strike (DOS, 1998)
54		Bustout! (Windows, 2000)
54		DriftZone (Windows, 2000)
54		Gravity Force (DOS, 2000)
54		Quadnet (DOS, 1998)
54		Mission Cobra 98 (DOS, 1998)
53		Blaster! (DOS, 1997)
53		Mini Ghost (Windows, 2017)
53		Nelda Nockbladder's Anatomy Lesson (Windows, 1997)
53		The Fourth Generation (DOS, 1997)
53		Atomic Bomberman (Windows, 1997)
53		Orbt XL (Windows, 2017)
53		N (Windows, 2004)
53		CHAMP Asterocks (DOS, 1997)
53		Super Bubble Mania (DOS, 1997)
53		Betamax (DOS, 1997)
53		Mono Space (DOS, 1997)
53		The Worlds of Billy (DOS, 1997)
53		Starcom (DOS, 1997)
53		Iji (Windows, 2008)
53		Akane (Windows, 2018)
53		Super Crate Box (Windows, 2010)
53		Hydorah (Windows, 2010)
53		Yongzhe Paopao Long (DOS, 1997)
53		Lazarus (DOS, 1997)
53		FreeStrike (Windows, 2001)
53		Bit Blaster XL (Windows, 2016)
53		Super Methane Bros (Windows, 2001)
53		UFO-Hunt 2001 (Windows, 2001)
53		Buggers (Windows, 2001)
53		Intensity XS (Windows, 2001)
53		GFID Advanced Place: Project φ (Windows, 2001)
53		Intensity XS: ReCharge (Windows, 2001)
53		Hornado (Windows, 2001)
53		TAGAP: The Apocalyptic Game About Penguins (Windows, 2007)
53		Squirm (Windows, 2018)
53		Hurrican (Windows, 2007)
53		Nebula Fighter (DOS, 1997)
53		Realm (DOS, 1997)
52		Alien Rampage (DOS, 1996)
52		Polandball: Can Into Space! (Windows, 2016)
52		Bomberman (DOS, 1992)
52		MURI (Windows, 2013)
52		Handsome Mr. Frog (Windows, 2016)
52		Firewind (DOS, 1996)
52		Cyber Police (DOS, 1996)
52		Abductor (DOS, 1996)
52		Pac 2000 (DOS, 1996)
52		Xenophage: Alien BloodSport (DOS, 1996)
52		TowerFall: Ascension (Windows, 2014)
52		Stargunner (DOS, 1996)
52		Stillhunt (DOS, 1996)
52		Bionic Commando: Rearmed (Windows, 2008)
52		Abuse (DOS, 1995)
52		Pink Hour (Windows, 2014)
52		Shatter (Windows, 2010)
52		Kero Blaster (Windows, 2014)
52		Revolver360 Re:Actor (Windows, 2014)
52		Flashback: The Quest for Identity (DOS, 1993)
52		Aliens (DOS, 1996)
52		Iron Man / X-O Manowar in Heavy Metal (DOS, 1996)
52		Super Cyborg (Windows, 2014)
52		DOOM 2D (DOS, 1996)
52		Bubble Bobble Quest (Windows, 2002)
52		Double Digger (Windows, 2002)
52		SideLine (DOS, 1996)
52		Stick Soldiers (Windows, 2002)
52		Entrance Gate (Windows, 2002)
52		MAZ! (Windows, 2017)
52		Alien Tequila (Windows, 2002)
52		BII-NARY: The War Against Pop-Ups (Windows, 2002)
52		StoneBreaker (DOS, 1996)
52		Flynn Sprint (DOS, 1996)
52		Choppy the Pork Chop (Windows, 1996)
52		SideLine (Windows, 1996)
52		Les Fous Volants (Windows, 1996)
52		Bombman! (Windows, 1996)
52		Hunter Hunted (Windows, 1996)
52		Vectoroids (Windows, 2002)
52		Super Transball 2 (Windows, 2002)
52		Super Hydorah (Windows, 2017)
52		Platypus (Windows, 2002)
52		Ricochet: Lost Worlds (Windows, 2004)
52		Juanito Arcade Mayhem (Windows, 2017)

Notes: Games similar to Space Fortress, Games like Space Fortress, Pixelmusement, Pixelmusement, DOS, Action, Sci-Fi, Futuristic, Arcade, Shooter, Side view, Fixed, Flip-screen, PC, Game Similarities.