Top Defense looks like a tower defense game, but it's actually an action-oriented defense game. From an aerial view, you have to use a variety of weapons to prevent enemy vehicles from reaching your missile silos. Your weapons take time to recharge, so you will need to use them as efficiently as possible. Your energy regeneration increases after each wave of enemies. When you have enough free energy, you can plug a new weapon into your system and upgrade the weapons that are already in your system.