Sphere is an open source integrated development environment designed to create 16-bit SNES/Genesis style role-playing games, such as Final Fantasy, Phantasy Star, Legend of Zelda, Star Ocean, etc.
It uses a cross-platform environment, working for both Windows and Linux.
Though Sphere was designed to make RPGs, because of the flexibility of a scripting language it can be used to make almost any other type of game.
Recent versions of Sphere also support basic 3D graphics functions using the OpenGL video driver. However, it is more complicated to use than the 2D graphics functions and is still in early stages.