Digital Combat Simulator World (DCS World 1.5) is a free to play combat flight simulator developed by Eagle Dynamics (ED). It includes a free Sukhoi Su-25T attack aircraft and TF-51D Mustang, and is extensible through additional DCS modules as well as user-made add-ons and mods. While the Su-25T and TF-51D are free, modules produced by third parties and Eagle Dynamics are usually only available with a payment. This all allows the creation of real-world combat missions. DCS World allows both realistic game play and more simplified game play to suit the player.