main.rb

require 'kaffeh'

class SomeGame < Game
  def initialize(config)
    cfg = Config.new(config)

    Window.set_size cfg.get?('width', 320), cfg.get?('height', 240)
    Window.set_title cfg.get?('title', 'Kaffeh!')

    cfg.save
  end

  def start
    p "start"
  end

  def update(delta)
  end

  def draw
  end

  def close
    p "close"
  end
end

Kaffeh.launch(SomeGame.new('./config.json'))