Tibia is a massively multiplayer online roleplaying game (MMORPG) created by CipSoft GmbH. It is one of the oldest MMORPGs and was considered most noteworthy in its early years; however, with the development of MMORPGs its popularity has grown much slower than others gaming communities. Its most unique aspect is being in a 2D environment, which is expected to contribute to the slow growth of the game as the gaming community rapidly shifted to 3D. It was first released in January 1997.[3] It is a free game which is open to the public, though players have the option to pay a fee in order to upgrade to a premium account, granting special in-game benefits, including additional areas to explore, access to vocation promotions, and extra spells.
You can get the engine for the game as well as the server client at Tibia.
You can easily change the sprites, spells, game client design, and more.