| Aero the Acro-Bat 2 (Aug 8, 1994 prototype) | 8 August 1994 | SNES | Action | - |
| Aero-Cross (Nov 26, 2010 prototype) | 26 November 2010 | Xbox 360 | Racing | ✓ |
| AeroGauge (Japanese demo) | | Nintendo 64 | Racing | - |
| Afro Samurai (Dec 1, 2008 prototype) | 1 December 2008 | Xbox 360 | Action | - |
| Afro Samurai (Oct 30, 2008 prototype) | 30 October 2008 | Xbox 360 | Action | - |
| After Burner Climax (Dec 11, 2009 prototype) | 11 December 2009 03:43:31 | Xbox 360 | Action, Shooter, Vehicular Combat | - |
| Aftershock (May 3, 1995 prototype) | 3 May 1995 15:04:20 | PlayStation | Shooter | - |
| Agaju: The Sacred Path of Treasure (Prototype) | | Gizmondo | Adventure | ✓ |
| Agartha (Apr 17, 2001 prototype) | 17 April 2001 | Dreamcast | Survival Horror | ✓ |
| Agartha (Apr 18, 2001 prototype) | 18 April 2001 00:23:42 | Dreamcast | Survival Horror | ✓ |
| Agartha (Mar 5, 2001 prototype) | 5 March 2001 16:34:14 | Dreamcast | Survival Horror | ✓ |
| Agartha (Mar 9, 2001 prototype) | 9 March 2001 | Dreamcast | Survival Horror | ✓ |
| Age of Booty (Jun 24, 2008 prototype) | 24 June 2008 | Xbox 360 | Real Time Strategy | - |
| Age of Booty (May 28, 2008 prototype) | 28 May 2008 | Xbox 360 | Real Time Strategy | - |
| Age of Empires (Aug 15, 1997 prototype) | 15 August 1997 | PC | | - |
| Age of Empires 2 - Age of Kings (Feb 22, 1999 prototype) | 22 February 1999 | PC | RTS | - |
| Age of Empires 2 - Age of Kings (Jul 17, 1998 prototype) | 17 July 1998 | PC | RTS | - |
| Age of Empires 2 - Age of Kings (July 1, 1999 prototype) | 1 July 1999 | PC | RTS | - |
| Age of Empires 2 - Age of Kings (June 2, 1999 prototype) | 2 June 1999 | PC | RTS | - |
| Age of Empires 2 - Age of Kings (June 30, 1999 prototype) | 30 June 1999 | PC | RTS | - |
| Age of Empires 2 - Age of Kings (May 13, 1999 prototype) | 13 May 1999 | PC | RTS | - |
| Age of Empires: The Rise of Rome (Aug 5, 1998 prototype) | 5 August 1998 | PC | RTS | - |
| Age of Empires: The Rise of Rome (Sep 15, 1998 prototype) | 15 September 1998 | PC | RTS | - |
| Aggressive Inline (Aug 21, 2002 prototype) | 21 August 2002 | Xbox | Sports | - |
| Aggressive Inline (Aug 6, 2002 prototype) | 6 August 2002 | Nintendo GameCube | Sports - Skating | - |
| Aggressive Inline (Jul 29, 2002 prototype) | 29 July 2002 | Nintendo GameCube | Sports - Skating | - |
| Aggressive Inline (Mar 2, 2002 prototype) | 2 March 2002 | PlayStation 2 | Sports | - |
| Aggressive Inline (Mar 3, 2002 prototype) | 3 March 2002 | PlayStation 2 | Sports | - |
| Aidyn Chronicles: The First Mage (Apr 10, 2001 prototype) | 10 April 2001 14:55:18 | Nintendo 64 | Role playing | - |
| Aidyn Chronicles: The First Mage (Dec 5, 2000 Prototype) | 5 December 2000 | Nintendo 64 | Action | - |
| Aidyn Chronicles: The First Mage (Feb 1, 2001 Debug) | January 2001 | Nintendo 64 | Role-playing Game | - |
| Aidyn Chronicles: The First Mage (Feb 10, 2000 prototype) | 10 February 2000 13:21:13 | Nintendo 64 | Role playing | - |
| Aidyn Chronicles: The First Mage (Mar 2, 2001 prototype) | 2 March 2001 19:42:35 | Nintendo 64 | Role playing | - |
| Aidyn Chronicles: The First Mage (May 9, 2000 prototype) | 9 May 2000 07:45:51 | Nintendo 64 | Role playing | - |
| Air Fortress (Prototype) | | FDS | Shooter | ✓ |
| Air Sea Battle (Robert Coppock Demo) | | Atari 2600 | | - |
| Air Zonk (Prototype) | | TurboGrafx-16 | Platformer | - |
| AirBlade (Nov 8, 2001 prototype) | 8 November 2001 11:58:46 | PlayStation 2 | Sports - Inline | - |
| AirCars (Nov 14, 1994 prototype) | 14 November 1994 | Atari Jaguar | Action | - |
| AirForce Delta (Jun 18, 1999 prototype) | 18 June 1999 11:16:54 | Dreamcast | Flight Combat Simulator | - |
| AirForce Delta (Nov 30, 1999 prototype) | 30 November 1999 14:58:26 | Dreamcast | Flight Combat Simulator | - |
| AirMech Arena (Aug 15, 2014 prototype) | 15 August 2014 | Xbox 360 | Vehicular Combat | - |
| Airblade (Sep 16, 2001 prototype) | 16 September 2001 18:49:31 | PlayStation 2 | Sports | - |
| Airburst (Jul 13, 2008 prototype) | 13 July 2008 | Xbox 360 | Action | ✓ |
| Airlock (prototype) | | Atari 2600 | Action | - |
| Akira (Prototype) | | Sega Mega Drive | Action | ✓ |
| Akuji the Heartless (Oct 14, 1998 prototype) | 14 October 1998 11:28:52 | PlayStation | Action | - |
| Akuji: The Heartless (Nov 11, 1998 prototype) | 11 November 1998 | PlayStation | Action | - |
| Akuu Senki Raijin (Oct 14, 1987 prototype) | 14 October 1987 | FDS | Shoot 'Em Up | - |
| Aladdin (Aug 13, 1993 prototype) | 13 August 1993 17:50:24 | Sega Mega Drive | Platformer | - |