z3r0d4y — a.k.a. Zero Day, a.k.a. ゼロデイ — is a competitive game played with one admin facing off against 1-3 hackers. The admin aims to fix vulnerabilities in a computer system before hackers steal too much information. The admin wins by acquiring a certain number of progress tokens based on the number of players, and to make progress, the admin must perform "operations" multiple times successfully while avoiding interference from hackers. To do so, the admin will rely on timing and must secure sufficient credits. Each hacker wants to steal information before others can do so (and before the admin fixes the vulnerability, of course), and once a hacker steals a certain amount of information tokens, they win the game immediately. To do this, they need to gather information, interfere with the admin's operation, and install virus proxies.