Wave survival
Zombies arrive in waves; the run ends when your car does. Difficulty steps up near wave 10 and thickens again toward wave 25, so survivability buys income at those walls. Your best distance — measured in studs — is the tracked record, and it is a progression requirement: the IAMPRO code required 1,000 studs before paying out.
Deep dive: the wave survival guide.
Cash economy
Combat pays: kills and wave progress convert to Cash, and Cash buys weapons, defenses, and car upgrades. Clear speed is your income rate — the faster a build clears a band it can finish, the more it earns per hour. Codes have documented the only fixed payouts: 500, 1,000, and 5,000 Cash.
Deep dive: the cash system reference.
5-player servers
The API caps servers at 5 players, so a full friend group fits one run. Builds stay personal — weapons, defenses, and Cash are per-player — and the Passenger Seats code reward shows car capacity is upgradable. Groups win by assigning roles, not sharing loadouts.
Deep dive: the server planner.