It's a beautiful little app, if only it would function properly. It seems poorly optimized; the controls are too vulnerable to input lag on lower-end phones. (My phone runs other apps and games without issue.) If I build anything other than a very small map, the (what initially felt subtle) input lag doesn't affect my ability to rotate or zoom the map, but ruins the one-finger controls. Instead of single-tap building and long-tap destroying, single-tap will destroy, and nothing can be built.