You have 200 units limit (unlimited units, i.e. 200 is maximum for the game engine) and 2x the money limit. You and the computer gain money a lot faster.
War in its purest form. Summon troops , kill , repeat. Defend your country by sending the right types of troops to the enemy units to destroy them. Each unit has different abilities, so recruit the correct unit to counter your opponent.
Use WASD KEYS or MOUSE to select unit, when you have enough money it will be recruited automatically.
Drag MOUSE on the minimap to move camera.