In the early days of videogames, Midway scored big points with a game called Gun Fight. In that game, two players each controlled a cowboy whose task was to gun down the other before being shot himself. Complicating the duel were on-screen obstacles like cacti and stagecoaches. It was a simple gameplay concept, but an effective one. Like other home video game manufacturers, Magnavox couldn't resist copying this little gem. Neither could they resist appending yet another pointless sci-fi theme to it, and the result is Showdown in 2100 A.D., the game where futuristic cowboy androids shoot it out for some unfathomable, futuristic cowboy android reason.
All kidding aside, Showdown in 2100 A.D. actually can be a pretty good game. Magnavox's cartridge does not provide Gun Fight's variety of obstacles, but relies only on the mutant trees of the future, which ricochet bullets at wild angles. Shoot one and that bullet could end up anywhere, even straight back at you. This adds some much needed unpredictability in a game that would otherwise get really boring, really fast. Two players can face off, or one player can tough it out against the incredibly inept computer. The computer's hijinks add a whole new dimension to the game, and I suggest reading the In-Depth Review to find out all about it.
Showdown in 2100 A.D. is a straightforward, early-'80s-style arcade contest at its purest. You won't find a lot of depth here, but if all you want is an uncomplicated shootout, man against man (or machine against machine), this is a fine choice.