Wii Play - Tanks

I have always thought that level 20 was the last level in Tanks, but two weeks ago I was presented with level 21, and then 22, and 23. It was crazy. Yesterday I played and got to level 50. I only had one guy, and my finger slipped off the remote, so I died instantly. The other tanks were blank and shot fast missiles. Did you guys know about this? I am too lazy to find out what the final level is - maybe one of you can tell us.