Info from the Flixel website. "Flixel is an open source game-making library that is completely free for personal or commercial use. Written entirely in Actionscript 3, and designed to be used with free development tools, Flixel is easy to learn, extend and customize."
FeaturesFlixel includes some basic features common to many game engines or other game libraries.
- Display thousands of moving objects
- Basic collisions between objects
- Group objects together for simplicity
- Easily generate and emit particles
- Create game levels using tilemaps
- Text display, save games, scrolling
- Mouse & keyboard input
- Math & color utilities
- Record and play back replays
- Powerful interactive debugger
- Camera system for split screen
- Pathfinding and following
- Easy object recycling
Homepagehttp://flixel.org
This would have to be one of my top picks for game development packages with medium skill level needed. Another great feature why I would choose this over some of the others is it can be used for commercial use. The website doesn't look like much but the more you read about what can be done, viewing the demos and playing some of the games, the more you'll see how good this really is.
To see what can be achieved, take a look at this game called Diamond Hollow 2
http://www.kongregate.com/games/Arkeus/diamond-hollow-ii
Take the time to learn what this package can achieve and you might be surprised.