Interesting that people are trying to dissuade the OP from using GameMaker. From reading his post it appears he is doing very well for himself and most importantly he is happy. I don't see much incentive for him to learn a completely new tool at this point.
"I'll miss the sea, but a person needs new experiences. They jar something deep inside, allowing him to grow. Without change something sleeps inside us, and seldom awakens. The sleeper must awaken."