The game (probably because it's a PoC) uses the width of your display window as the width of the game, instead of a display independent width. So if you have a

The game (probably because it's a PoC) uses the width of your display window as the width of the game, instead of a display independent width. So if you have a narrower window, the tanks will be closer. In the narrow confines of a smartphone this means the tanks are right next to each other.