Unity is a multiplatform game development tool, designed from the start to ease creation. A fully integrated professional application, Unity just happens to contain the most powerful engine this side of a million dollars.
Extremely easy to use engine. It does a lot of the heavy lifting for you. I'm extremely grateful to have found such an intuitive engine to use for my first mobile game. I recommend everyone starting out in Game Design to give Unity a try. Pro does cost money, but you can still do a lot of the things you want to accomplish using Unity Free, in addition to monetizing your games. The editor does glitch out here and there, but the abstraction it provides is simply unbeatable.