I've tried downloading it a few times, each time the Jar file is corrupt. I've completely opened up permissions and used two different extractors.
Basically if you extract the entire time from the Win or Jar file, it gets all the way to the end and then lets you know there is a corrupt file. If you just skip it, then the game will not start. If you retry, it keeps failing. When you try to extract JUST the Executable Jar File (3GB) it gets all the way to the end and gives the same corrupted error.