u/fagnerbrack

A decompiled 2004 RuneScape 2 client reveals an obsessive effort to waste no bytes, squeezing a 3D world of thousands of players through roughly 5 KB/s. The Java applet sandbox forced everything down one TCP connection, and the server advanced in 600ms ticks, so the battle came down to bytes, not latency. A walk sends only path corners as coordinate deltas, so a single step north costs seven bytes. Each client mirrors nearby players, and updates carry only what changed: bit-packing turns "nothing changed" into one bit and a step into seven. New arrivals get positions relative to you, ten bits instead of thirty-two. The protocol enciphers only the opcode byte and mangles others to deter cheats.