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Well, at least they have Unity.
As for C++, every time I look at their documentation with hopes they got something sane, it brings back bad memories of Symbian C++ with their two step construction, placement new, naming conventions to denote method behaviors and many other headaches.
Which developer in their sane mind whats to work with that again?
That is not "every Game Engine" especially when half of those are stupid HTML/JS frameworks like Sencha that no one will touch.
The other one is a generic Game Maker which isn't very good from what I've used it, and its honestly not very good.
Unity and Project Anarchy are the only two competent offerings there, and even that isn't a whole lot. Certainly not every game engine.
Marmalade is actually layered on top of Cocos-2dx but thats never been performant (check Cut the Rope on Windows RT)