In this tutorial, I'll explain how to develop a very simple Defender-style game using the open-source Flixel 2 game library for Flash. Flixel was written by Adam Saltsman and extracted from a couple of his own Flash games, including Gravity Hook, Fathom and Canabalt. There is also an iPhone version lurking around the corner, which will make Flixel even more useful.
Flixel is an AS3-only framework which means that we don't need Adobe Flash CS4 at all. No movieclips, no timeline, no library and no high price tag. Instead, we will do everything with pure code and bitmap spritesheets.