Can setup account and user names. Users can refer there friends to join. Link account to google play or Icloud account so they can purchase in game item with fiat. or connect to wallet for crypto native to purchase in game item using crypto. Ones account setup, user can compete for leaderboard and get compete for prize. Also allow user to keep history of their own game play to keep track of their most zombie killed, highest score and/or highest waves. Most used character etc.