The level files are 503ing, but it looks like the level counter is still incrementing if I go out of the exit and back in again. You might want to add some response code validation in.
GET http://alex.nisnevich.com/untrusted/levels/10_ambush.jsx 503 (Service Unavailable) jquery.min.js:6
GET http://alex.nisnevich.com/untrusted/levels/11_robot.jsx 503 (Service Unavailable) jquery.min.js:6
GET http://alex.nisnevich.com/untrusted/levels/12_robotNav.jsx 503 (Service Unavailable) jquery.min.js:6
GET http://alex.nisnevich.com/untrusted/levels/13_robotMaze.jsx 503 (Service Unavailable) jquery.min.js:6
GET http://alex.nisnevich.com/untrusted/levels/14_crispsContest.jsx 503 (Service Unavailable) jquery.min.js:6
GET http://alex.nisnevich.com/untrusted/levels/15_exceptionalCrossing.jsx 503 (Service Unavailable) jquery.min.js:6
GET http://alex.nisnevich.com/untrusted/levels/16_lasers.jsx 503 (Service Unavailable) jquery.min.js:6
GET http://alex.nisnevich.com/untrusted/levels/17_pointers.jsx 503 (Service Unavailable) jquery.min.js:6
GET http://alex.nisnevich.com/untrusted/levels/19_documentObjectMadness.jsx net::ERR_CONNECTION_REFUSED jquery.min.js:6
GET http://alex.nisnevich.com/untrusted/levels/20_bossFight.jsx net::ERR_CONNECTION_REFUSED jquery.min.js:6
GET http://alex.nisnevich.com/untrusted/levels/21_endOfTheLine.jsx net::ERR_CONNECTION_REFUSED