Have you guys seen [this](http://alexnisnevich.github.io/untrusted/)? It's a webgame you play by modifying the javascript that generates the levels. For example, removing
for (x = 5; x <= map.getWidth() - 5; x++) {
map.placeObject(x, 3, 'block');
map.placeObject(x, map.getHeight() - 10, 'block');
}
from level 1 deletes two of the walls, allowing you to escape. It's really fun, but I appear to have run into a bug (in part of the code that I can't edit) on level nine and I'm waiting on a dev response...