Creating a game using Flash CS4 and Actionscript 3 is a great way to start the gamemaking career you've always dreamed of. If you want a game company to hire you, it will really help if you have at least one simple, creative game in your portfolio. If you want help with this undertaking, this seven-part video series will teach you how to create a simple spaceship shooting game from start to finish. The first three videos cover physics topics like acceleration, friction, and velocity, the adjustment of which will govern how your character moves. The next four cover creating shooting, enemies, explosions and enemy AI. Once you've got all of that, you've got yourself a game!
Download AS3 scripts used in the series here.