Well game design and development requires quite a few things to make. A decent flash game can be made by one person and you can actually learn how to make one over the internet, but games that go on the consoles typically take about 100 or more people working together to make. It requires programmers who make the code that causes objects in a game to interact with each other, and basically are the backbone of any game, then there are those who come up the the level designs, sound engineers who deal with composing music, as well as sound effects and voice acting. There are artists who come up with concept art,and 3D models. Then there is quality assurance(aka game testers) A lot goes into making a game, and its basically up to you what part you want to work on when choosing to go into game design, though I would suggest staying away from game testing.
