None.
You can use the Tiled to edit levels.
The sample_game contains a simple game involving trading of goods and some adventure game story elements.
Make sure you talk to all of the characters multiple times, as new story elements become available.
To learn about the engine, I suggest you look at the sample_game/spiced.chai source file. Then open the sample_game/resources folder and look at the .tmx map files. You can open them with Tiled then export them as json files, overwriting the existing json files in the directory. Relaunch the game and see the differences.
Please note that most of the artwork comes from opengameart here: http://opengameart.org/content/oga-16x16-jrpg-sprites-tiles
All copyrights for artwork apply.