Anniversaries/April 21
From Sega Retro
April 21 (add)
- 1984 - Astron Belt is released for the MSX in Japan.
- 1986 - Wonder Boy is released in Arcades for the Sega System 1 board alongside Comical Machine Gun Joe and Ghost House for the Sega Master System in Japan.
- 1989 - Power Drift & Mega Drive, a LaserDisc, is released in Japan.
- 1990 - Toki no Keishousha: Phantasy Star III is released for the Sega Mega Drive in Japan.
- 1991 - Formula, a CD, is released in Japan.
- 1993 - The Mega Commander, a third-party controller accessory, is released in Japan.
- 1994 - Soul Star, a Demo Disc, is released for the Sega Mega-CD in the United Kingdom.
- 1995 - Rampo Virtual Guide Book, a book, is released alongside Chaotix for the Super 32X in Japan.
- 1999 - L.A. Machineguns Original Soundtrack and Zombie Revenge, both CDs, are released in Japan.
- 2000 - Red Dog: Superior Firepower is released for the Sega Dreamcast in Europe.
- 2001 - Planet Harriers The Original Soundtrack, a CD, is released in Japan.
- 2003 - Sonic Darts is released for i-mode 503i compatible phones through Sega's Sonic Cafe portal in Japan.
- 2004 - Fantasy Arena, a medal game, is released in Japanese Arcades.
- 2006 - Football Manager Handheld is released for the PlayStation Portable alongside Condemned for Windows PCs in South Africa.
- 2008 - Phantasy Star III: Generations of Doom is released for the Wii Virtual Console in North America.
- 2009 - Phantasy Star is released for the Wii Virtual Console in Japan.
- 2010 - Crackin' DJ Complete Album and Senjou no Valkyria Song Collection, both CDs, are released alongside After Burner Climax for the Xbox 360 and PlayStation 3 in Japan. After Burner Climax is released for the Xbox 360 in North America, Europe, and Australia while Sonic the Hedgehog 2 is released for iOS in North America and Europe.
- 2011 - 3D Mahjong Geki Pai is released for Android devices in Japan. Golden Axe II and Streets of Rage 2 are released for iOS in North America and Europe.
- 2015 - Dead or Alive 5 Last Round is made available for digital download on the Xbox One in Japan, North America, Europe, Australia, South Korea, and Hong Kong.
- 2016 - Drama CD Puyo Puyo Vol. 8, a Drama CD, is released in Japan.
- 2017 - An Open Beta for Warhammer 40,000: Dawn of War III starts for Steam in North America.
- 2021 - Wonder Boy: Asha in Monster World is released for the PlayStation 4 in Japan.
- 2022 - Aleste Collection: Music Album, a CD, is released in Japan. Space Harrier II, Shining Force II, and Sonic the Hedgehog Spinball are released for the Nintendo Switch Online service for the Nintendo Switch in North America.