Is it possible to import a project (game) from Flash cs4 to FlashDevelop?
Is it possible to import a project (game) from Flash cs4 to FlashDevelop ? And how will work things like the timeline ?
It's not this easy if you have code in the timeline, you will have to do without timelines. You can import assets together with their timeline code, if they are working as you intend them to, otherwise you will be unable to edit that code in any way. Yes, there is a complex method addFrameScript() that allows you adding some code to a MovieClip, but it overwrites whatever was there the first time. Actually, it's better to not code on the timeline, as you don't have full control over execution flow, and an omission of some line on frame X can cause weird implications on either subsequent frames or on the game integrity in total.
FlashDevelop can parse SWFs for resources, SWCs too, but cannot open a FLA file, so you will have to do much work to move your game out of Flash CS. I went similar way when my trial use of Flash CS4 expired, I didn't code much in timeline except self-animating movie clips which I intended to be repeated infinitely, eventually I went around MovieClip objects altogether in favor of less sophisticated but highly more alterable Sprite class.