F4L is an open source development environment like Macromedia Flash, a multi-platform format(swf/svg) widely used for web applications. its a BETA version which means no real ability to use for production.
A pain to get to work on Ubuntu, and Mint, but I managed thanks to a dude that posted a video on youtube. (http://www.youtube.com/watch?v=JooYSc6TftU) Alongside that motion tweaning doesn't work as like adobe flash did as a matter of fact I couldn't get anything to work except some brushes, and the eraser tool. Even the delete layers didn't work. All you can really do is make some corny design on it and export the image as a swf. This program needs a big improvement, cause right now it's nothing but trash, cause nothing works, yet I don't see why people keep recommending a program that can't do a simple animation task!
I´d just have a problem decompressing the file it says it's corrupted. tuve un problema descomprimiendo el archivo,dice que esta dañado.