Starting a project creating a flash game and can't afford to spend money on a license for the newer Flash CSx. I have an old license of Macromedia Studio MX that comes with Macromedia Flash MX v6.0 which has Actionscript 1.0. My question is, are all of the syntax for Actionscript 1.0 and the finalized output SWF still compatible with the new/future flash player plugin?
It definitely will work!
You should check if it works correctly in all its parts, because some behaviors has been slightly modified (but this apply much to old SWF file, not to one made present time).