The Astrocade was a competitor to the Atari 2600 and Odyssey2 back in the late 70's. It never reached much popularity, but it had some pretty good games, including Space Fortress and an excellent "port" of Wizard of Wor. Recently there was also a very good reproduction of Warlords done for the system. Note that the system output very odd analog video, and many upscalers may have issues with it.
To check out the core, take a look here:https://github.com/MiSTer-devel/Astrocade_MiSTer
As always, please read the github instructions for setting up the bios and controls. If you're interested in learning more about the system, the following site has a nice collection of information and homebrew:http://www.ballyalley.com/