Engines and Distribution Tools

for visual novels

http://www.renpy.org/ - Ren'Py, dedicated VN engine
http://nscripter.insani.org/ - ONScripter, dedicated VN engine (translated)
http://www.bladeengine.com - Blade, dedicated VN engine (only the light version is free, some nags)

http://inform7.com/ - Inform 7 design system, greatly improved over Inform 6
http://www.inform-fiction.org/ - Inform 6, based on the Infocom format
http://www.adrift.org.uk/cgi/new/adrift.cgi - Adrift, needs Adrift Runner to play adventures
http://www.generalcoffee.com/hugo.html - Hugo, needs runner software to play adventures

http://www.adventuregamestudio.co.uk/ - a free engine for making point-and-click classic adventures
http://www.adventuremaker.com/ - object-oriented adventure engine (only the light version is free)
http://www.gamemaker.nl/ - a free game-making engine (only the light version is free, some nags)
http://www.alice.org/ - a free game-making software