How about a 3d style that transforms and gets cooler as you get marks. You unlock the full awesome style once you 100% the tank.

So it has 5 steps: Base, 1 mark, 2 mark, 3 mark and 100%

I’d like such a thing in the game. It needs to be super awesome though. People will push marks like crazy and its gonna be a reason for potatoes to learn how to actually play.

I’d start with a new line so the unicum lords can experiment the thrill of unlocking the skin and not just auto-unlock it.