Add multiplayer

Minimal checklist:

1. Add a NetworkComponent to the entities you want replicated (usually on a prefab). Set authority: Server for enemies/pickups, Client for players, Shared for walls.
2. Set syncTransform (and syncSprite if the sprite changes).
3. Set prefabPath to the prefab the other side should instantiate.
4. Guard simulation in scripts:

local function shouldSimulate()
    if not Net.isNetworked() then return true end
    return Net.isServer()
end

function Enemy:onUpdate(entity, dt)
    if not shouldSimulate() then return end
    -- move, animate, collide
end

1. Launch with --server / --client, or use the editor's Play Multiplayer button.

Players are spawned by the engine from the Client-authority template's prefabPath; Lua cannot instantiate prefabs. Read a client's input on the server with Net.input(entity).

See Engine → Networking, Editor → Multiplayer, and Lua → Net.