2004 RuneScape fit a multiplayer RPG into 56k dial-up

The 2004 RuneScape client ran as a Java applet over a single TCP connection, using a 600 ms server tick and a lightweight ISAAC stream cipher that encrypted only the one-byte opcode of each packet. By tightly packing game state updates and limiting bandwidth to roughly 5 KB/s downstream, Jagex delivered a 3D world with thousands of concurrent players to dial-up users.