The premise of Touch Battle Tank 3D is gloriously simple. You are the blue tank or the red tank. Blow up all the other tanks. That's it. That's everything. All you need to worry about for more than 70 levels is the escalating threat level and minor mechanical questions such as how, exactly, a tank is able to leap over missiles.
There really isn't much here unless you really, really like blowing tanks up. The gameplay is elementary, even with attempts at minor complications in the more agile red tank (which is faster, can jump over missiles and which you will never use, thanks to its limited health) and different types of enemies.
The basic skills you learn in breezing past the first 10 or so levels stand you in good stead for the rest of the game and your own vehicle gains extra health as you progress. It couldn't be more straightforward if it tried and the complete lack of any kind of tutorial reflects this.
Things can rapidly get frustrating if you're not quick off the mark, however, and aside from some minor variations in enemy types and blocking walls, there's zero interest to be had in the level design. After the first few levels it's really only interesting for the genuinely committed tank destruction enthusiast.