lol.....level 20 has two invisible tanks. No wonder you haven't seen them.

My little bro got 137 Tanks and got to like Level 35... HE GOT A PLATINUM.

By the time he had gotten to that level, he had killed 8 of the ghost tanks that are on the Level 20.

Dunno how many missions there are...

I tallied 540 kills the other day and got a mission complete message just like you get when completing mission 20 the first time. I did not get any other medals than the platinum medal. Kind of crazy since platinum comes fairly early (roughly 130 kills or so). If you think the invisible tanks are tough... wait till you face the black ones. Even worse is the black and the invisible together. I can and have played too many hours What a fun game! Does anyone know if it goes beyond 540 kills?

Someone here says he had gold at 44 tanks??? I didn't even get gold at 73 tanks!!!
I got my gold when I completed the 20 levels.

I only got to the stupid old purple tanks. How do you kill those things? I had 4 or 5 lives left and they were gone in less than 30 seconds!

What do the black tank do?