NES Four Score
Games released prior to the Four Score which support more than two players, require the players to alternate turns using the same set of two NES controllers. Other games that originally featured support for more than two players, such as some arcade games, decreased the number of simultaneous players to two when ported to the NES.
On the Four Score, there is an option to switch between two-player and four-player modes and turbo A and B buttons that give any of the connected controllers a turbo boost. The Four Score can also be used as a controller extension cable because the wire which leads from the accessory to the NES is several feet in length.
The Four Score is similar to the previously introduced NES Satellite, a device that allows four players to connect to the NES and extends the range using infrared wireless communication.
These games are compatible with the NES Four Score, for more than two concurrent players.
- 8-Bit Xmas 2011
- Bomberman II
- Championship Bowling 
- Danny Sullivan's Indy Heat
- Gauntlet II
- Greg Norman's Golf Power
- Harlem Globetrotters
- Kings of the Beach 
- Magic Johnson's Fast Break
- Monster Truck Rally
- NES Play Action Football
- A Nightmare on Elm Street 
- Nintendo World Cup 
- R.C. Pro-Am II
- Rackets & Rivals
- Roundball: 2 on 2 Challenge
- Spot: The Video Game
- Smash TV
- Super Off Road
- Super Jeopardy!
- Super Spike V'Ball
- Swords and Serpents
- Top Players' Tennis
The 4-Players Adaptor (4人プレイヤーズアダプタ?) was a licensed peripheral released for the Famicom in Japan by Hori. It is the Famicom's equivalent to the NES Four Score. Its purpose was to allow up to four players to play simultaneously in compatible games by allowing for additional controllers to be connected through the console's expansion port. The adapter also features a switch that allows the first two players to use external controllers as well in lieu of the standard Famicom controllers, giving each player the choice to use an external controller. Many of the titles in Technōs Japan's Kunio-kun series supported the adapter.
- Downtown Nekketsu Kōshinkyoku: Soreyuke Daiundōkai
- Ike Ike! Nekketsu Hockey Bu: Subette Koronde Dai Rantō
- Nekketsu Kakutō Densetsu
- Nekketsu Kōkō Dodge Ball Bu
- Nekketsu Street Basket: Ganbare Dunk Heroes
- Kunio-kun no Nekketsu Soccer League
- U.S. Championship V'Ball
- "Nintendo Entertainment System Accessories". Giant Bomb. 22 October 2013.
- "NES Four Score adapter converted for USB use". Retro Game Network. 22 April 2013. Retrieved 4 January 2014.
- "NES: Four Player Fun?". Retrieved 3 January 2014.
- "Kings of the Beach (NES)". NintendoLegend.
- "Retro Gaming Review: A Nightmare on Elm Street (NES)". Daily Dead. 15 July 2011.
- "Nintendo World Cup Review". allgame.
- "Nintendo Entertainment System / Famicom Documentation". Mednafen. 12 September 2013.
- "Famicom Four Player Adapter". Famicom World. 16 February 2011.