All-in-one program for creating 2D scrolling games. Compile your games into stand-alone .NET executables or customizable C# source code. The IDE and framework are build on OpenTK, which wraps OpenGL, so generated games can be cross-platform.
The Open Game Studio is a project that targets game developers (mostly hobbyists). The goal of this project is to create a development environment that focuses on developing the game content. An engine that can run the created games is in work too.
Mallard is a graphical game design package, akin to many applications for Windows such as The Games Factory, RPG Maker, Game Maker, etc. It is written in Python with wxWidgets and PyGame, and therefore should support any OS which supports Python and SDL.