Why does my notebook get so hot

Your 'Notebook" consumes power, when you play a game your processor (cpu) uses power to calculate all kind of things. Power will pass through your device, and processor has resistors. When power goes through them they get warm, so when you play a game it uses a lot of power and it creates a lot of heat. When a 'notebook' manufacturer doesn't design much heat dissapating in the device it won't loose its heat quick so it gets warm. Also when you charge your device it will get warm because of the electricity flowing through your device. And your device also makes a lot of heat by making your screen light up, just like a lightbulb.