1. Companies starting with R:

      Radical Entertainment
      Radica
      Radience Software
      Radio Shack
      Rainbird
      Rainbow Computing
      Rainbow Connection Software
      Rake In Grass
      Ralston Foods
      Rampant Games
      Rare Ltd
      Raven Software
      Razorworks
      ReadySoft
      Real Arcade
      Realism Entertainment
      Reality Gap
      Reality Pump
      Realtime Worlds
      Rebellion
      Rebelmind
      Red Marble Games
      Red Octane
      Red Panda Games
      Red Storm Entertainment
      Reflexive Entertainment
      Relic Entertainment
      Remedy
      Renegade Ware
      Rennaisance Technology
      Renovation
      Respawn Entertainment
      Retrozone
      Rigor Mortis Software
      Rino Software
      Ripcord
      Ritual
      Rival Interactive
      Riverdeep
      Riverman Media
      Robomodo
      Rock Star Games
      Rocksteady
      Rogue Entertainment
      Roklan Software
      Rooster Games
      Rubin Microsystems
      Ruffian
      Runic Games
      Running With Scissors
      Rusty Axe Games

      Note: bolded names indicate companies that released a game within the last twelve months.