Every human own billons of nanoscopic cells.
Some of these cells are doomed to protect our organism and fight foreign organisms. Use your cell colones to slowly progress and take over the map.
The city has been taken over by a hostile army. Build up your army with heavy military hardware and take back the streets and try not to destroy the city while you are at it.
It's the final stages of WWI. Victory is in sight, but there are still battles to be fought and won. As part of the allied war effort, it is your task to protect selected bases, wipe out remaining German forces and bring an end to the war.