When creating Mine Shaft I knew absolutely nothing about Flash. It was my first go at it, and as a newbie I assumed that using the Flash IDE was the way to do it. I also assumed from reading a few short tutorials that AS2 would be a good point to start. How wrong I was!!!
Last month I decided to read up on AS3 and some other stuff for my upcoming project. I found FlashDevelop and the Flex SDK. It turns out you don't even have to pay a dime to create Flash content. FlashDevelop also turned out to be a million times nicer to code in. As I said, I am pretty (very) new to Flash development, but I have been programming Java and C# for a couple of years. Coming from the likes of Visual Studio, Flash was a nightmare to code in. FlashDevelop is heaven compared to it!
I am now on my way to creating my first pure AS3 project. It will be born from 100% Open Source and free software. For graphics I use InkScape. It's sort of backwards with the Y axis reversed and what not, but I actually prefer it to Flash.
My next game will be a "bullet hell" shooter mostly inspired by Ikaruga. Until then, have a great time! And be sure to try and beat the Mine Shaft high score.