Bad news: Oracle has disabled all applets that don't pay a lot for a certificate - yearly! The last working version for this site therefore is Java 7 update 45. This is obviously a security risk, so if you have an emulator set up or another box with older Java, you can enjoy these puzzles there.
BOO, ORACLE!
Also, Google Chrome now stopped supporting the Java plugin altogether. So it works only in Firefox.
IS EVERYONE ON CRACK?!?