A practical, end-to-end handbook on using Lua to build modern games — from core syntax to engine architecture, AI, netcode and shipping.

Multiplayer is the hardest part of game development.
This chapter covers the exact models used by:

• Fortnite
• Apex Legends
• Overwatch
• Rocket League
• Factorio
• StarCraft II
• Roblox
• Unity Netcode / Unreal replication

You will learn the following sync models:

1. Lockstep (deterministic strategy / SLG)
2. Snapshot interpolation (action games)
3. Client-side prediction & reconciliation
4. Entity replication (position/rotation/state)
5. Combat sync
6. Bullet/projectile sync
7. Lag compensation (server rewind, hit-scan)
8. Anti-cheat considerations

Lua is excellent for netcode:

Real-time multiplayer games must constantly keep each player’s view of the world in sync with the authoritative game server.
This is one of the hardest challenges in networked game development because:

• Networks introduce latency
• Packets get lost or delayed
• Input arrival times differ
• Players have unpredictable connections
• Tick rates differ between client and server
• Bandwidth is limited (especially mobile)

State synchronization (“netcode”) is the art of making every player experience smooth, fair, and consistent gameplay, despite these constraints.