In the yard, you will find a terminal for starting zombie waves and a board showing the level of difficulty of the current zombie wave. The first activation of the terminal won’t require any resources.
After killing the zombies you’ll be able to start a new wave (its difficulty will be higher) for free, i. e. without using a new electronic circuit.
If enemies are too strong and you leave the event, starting new waves will require an electronic circuit and the level of difficulty will be reset to the first one. In case of death, the level of threat is also reset and the next wave activation will again require an electronic circuit. That’s why we recommend you to realistically measure your powers. The reward for the last, 99th wave will be a special police chopper, good luck!