The is an arcade system developed and produced by Nintendo, first released in 1984. It is an arcade hardware that is based on that of the Nintendo Entertainment System, containing much of the console's chips and processors within. All games released for the system are ports of NES games, some being heavily altered to accommodate for the hardware. The system had a heavy focus on two-player cooperative play. The system was released in three different configurations - upright "VS. UniSystem" cabinets, upright "VS. DualSystem cabinets", and sit-down "VS. DualSystem" cabinets. Games are on chips that can be plugged into the board, allowing for one side to have a different game than the other.
Hardware
The VS. System was designed primarily as a kit to retrofit Donkey Kong, Donkey Kong Jr., Donkey Kong 3, Popeye, and Mario Bros. machines; as such, they require the same special monitor that these coin-ops use. These monitors use inverse voltage levels for their video signals as compared to most arcade monitors. Commercially available converters allow one to use any standard open frame monitor with the game. Almost all the games on the VS. System run on identical hardware powered by a Ricoh 2A03Central processing unit, the same found in the Nintendo Entertainment System but with the exception of special PPUs, or video chips designed for this circuit boards. Each chip contains a different palette that arrange the colors in different configurations chosen apparently at random. Most boards can be switched to a new game simply by swapping the program ROMs, though the appropriate PPU must also be used; if not, the game will appear with incorrect colors. Several of the later VS. games employ further measures of protection by using special PPUs which swap pairs of I/O registers or return special data from normally unimplemented regions of memory. Attempts to run these games in other VS. Systems will result in the game failing to even start. Some dedicated VS. double cabinets were produced which look like two games butted together at an angle. A single motherboard powers both games on those models. The Red Tent, a steel sit-down cabinet for the VS. DualSystem, allow play for up to four players simultaneously. This cabinet uses the same motherboard as the double cabinet. Because the VS. System has the same CPU that is in the Nintendo Entertainment System, VS. System games can be ported to the NES with modifications to the console including extra memory banks and additional DIP switches.
Version differences
Some games are different from their Famicom/NES versions. For example, VS. Super Mario Bros. is considerably more difficult than Super Mario Bros.; some of the levels were reused in for the Family Computer Disk System. The graphics are also different from their Famicom/NES counterparts; for example, VS. Duck Hunt has more details and animation sequences than its console counterpart.
Games
The following is a list of all known Nintendo VS. System games, however, it is believed more exist in the form of prototypes, unreleased and released only for a short period of time for market testing. The launch titles for the hardware are Vs. Mahjong and Vs. Tennis in or about February 1984.
