Excellent question Effigydrums, -again I feel your pain
. I used Flash 8. It's a tough question to answer, -since right now I'd say creating that in Flash went smoothly for me. BUT, I've been working with Flash for ~ 6 years & learning it (especially the ActionScript) has always been painful... I still consider myself a beginner with Flash (or I feel like a beginner with it).
The most challenging part of that Flash for me was doing the preloader. A big help for me has always been finding examples of successful ActionScript, and then tearing it apart & testing it. Change it, test it, change it, test it, etc. over and over. If you had asked me that question, before I had learned how to do the preloader, I would have answered, it SUCKS!! lol! And that's how it has gone with Flash. I can get through the basics easy, but as soon as I hit the (example), "How can I get all of the frames to align properly to the stage without having to align each frame to the stage for all 230 frames?" <-- It just seems to take a trip to the moon and back to learn the little 'trick' in getting around that time sink hole.