refactor Kiigame.checkIntersection into its own class (with unit test), make the treatment of secret category configurable, and configure it in latkazombit.js
rewrite play_ending, override it in latkazombit.js to handle the rewards
Refactored 'secret' items having no hit region to be configurable in latkazombit.js, but actually implementing #33 would be the best (data driven) thing to do
The whole play_ending could be latkazombit.js specific thing. An ending cutscene could be just a cutscene, and an ending picture could be just a room.
TODOs remaining: