LINKS AND DOWNLOADS
Flixel and FlashPunk are two separate Actionscript 3 game engines, but they’re very similar in look and feel. They’re both geared towards lo-fi 2d games (for example, the hit game Canabalt was built with Flixel, and Give Up Robot 1 + 2 were built with FlashPunk). Flixel is a little more geared towards platformers and tilemaps, while FlashPunk is more Game Maker-like with its depth sorting and fixed framerate options. Both have teamed up to create FlashGameDojo, a website for flash game development using the two tools. Users can post code snippets, tutorials, finished games, etc.
Tip: Their Getting Started tutorial is a great introduction to programming games in AS3.