I Build Complete Roblox Gameplay Systems

-- Modular. Server-authoritative.
local System = {}
System.__index = System

function System.new(player)
    local self = setmetatable({}, System)
    self.player   = player
    self.session  = Session.load(player)
    self.events   = Signal.new()
    return self
end

function System:save()  -- clean.
    return DataStore:safeSet(self.session)
end