Optikon is a free Windows based ( Mac and Linux can run via Wine ) level editor that takes a WYSIWYG approach to creating game levels using the Lua powered Love game framework.
Details of Optikon from the website:
Drag and Drop Level Design
Optikon is a simple drag-and-drop level designer which makes stunning 2D level design in LÖVE possible for everybody.
Optikon generates Lua code in real-time as you create your level, so that you don’t have to write a single line of code. Simply copy and paste this code straight into a .lua file to run your game, or click “Run” in Optikon to play your level in an instant.Built-in Code Editor
Optikon comes with a built-in Lua code editor so that you can do all your level design and coding in one place. The code editor comes with automatic Lua syntax highlighting to help boost your productivity.
Quick & Versatile Level Design
Optikon will give you the tools and performance needed to easily build large and complex levels. Add rulers as a visual aid, layer and quickly duplicate components to speed up level design.
Optikon is ultimately a code generator, creating Lua code for the Love framework. If you want to learn more about Lua and Love, check out our complete tutorial series available here. To see the Optikon editor in action be sure to check out the video below.