Need to add so many features? Why not make a fork?
PushButton Engine was one of the best Flash Game Engines that I had the pleasure to work with. It has a powerful and very well implemented entity-component framework with dozens of tools and utilities to make games easily. It has an xml specification that make the level creating very easy and extensible.
My fork consist in make some optimizations on the code (since I was working to make a game to a very limited device) and a GUI framework made from the scratch with labels, text fields, buttons, mouse/touch handling, etc. It is simple, fast and consistent. All I needed in that time.
Since I had to dig into the internal PushButton code, I learned a lot making this fork. I saw the beauty of using efficiently the tools that is available in ActionScript 3 and learned to use them. It’s very sad that PushButton Engine closed its doors. It was very promising and could change the Flash game development world.
I’ve been using my PushButton fork in the companies I worked since and until now, the engine still is enough to make games (and frameworks) safely and fast.