Well, it is obvious I haven't been around for a while. I have been busy studying and attempting to create a game engine
The reasons why I don't like to use a licensed engine is because I would be at the mercy of that engine's developers and corporate decisions. When one doesn't trust corporations, it is logical to find and build one's own resources. It takes longer, but I think the effort pays off in the long run.
It is going to be a challenge to implement the game design decisions I have in for the long term. In short term, it is a simple educational matching game. But as new versions of it are developed, Machine Learning for improving the difficulty and learning paths, complex AI for pathfinding,and finite state machine for the major entities will become necessary.