This game can't be found at System 16. According to Guru's old list, this is a prototype version of Tempest. Modified ROMs are included with Clay Cowgill's Tempest Multigame kit, but we need the originals. Aliens (Prototype) is an earlier Tempest prototype.
- Vortex at andys-arcade's Facebook page.
- Vortex video at andys-arcade's Facebook page.
- Vortex rumor at KLOV Forums.
- Vortex boardset owned by SafeStuff.com.
- Vortex mention at Unreleased Atari Arcade Games (btribble) at The Internet Archive.
- Vortex - June 26th 1981 Coin-op Engineering Status Meetings - Minutes.
- Vortex gameplay footage from Clay Cowgill's Tempest Multigame at YouTube.
- Interview with Dave Theurer from 1995 indicates owning a Vortex prototype.