Games that have been programmed from scratch without the use of any pre-existing game-making software.
Game engine developed by a independent game creator specifically for their game(s)
The Irrlicht Engine is an open source high performance realtime 3D engine written in C++. It is completely cross-platform, using D3D, OpenGL and its own software renderers, and has all of the state-of-the-art features which can be found in commercial 3d e
txtr is a small web based Python application come engine that allows you to turn interactive fiction into real time texting based text adventure games.
Untold Graphic Adventure Game System
Includes all versions of Unreal Engine.
Freeware development tools for Windows/Xbox offered by Microsoft