Before rushing into battle, stock up on weapons. Go to the "Weapons" section and install the ones you like and have available in the slots. During the game, change weapons using numbers on the computer or by clicking on icons on the phone. In the main mode, you need to kill a fixed number of enemies on each level. For this, you will receive game currency and new weapons. In the "Survival" mode, enemies never end, and their strength and number constantly increases.