Really well done game, over the top especially with the level editor and save files. The art style is good, but could use a better connection to the theme. The mechanic is really interesting and fun, nice job!
The level editor was actually very simple. Levels are stored as a 2-level array of block id's, by x and y coordinates. The mouse position sets the block of its x/y coordinate. Javascript exports the current levels array as json. Much less time consuming than typing out each block id manually.