Moai is the mobile platform for pro game developers, with an open source SDK and cloud-based game services for rapid development of iOS and Android titles, all built in the industry standard Lua scripting language.
Fantastic performance and cross platform support for all mobile and desktop platforms (and possibly the PlayStation console as well within the community), free and open source so you can code any special capability you may have in the future (unlike proprietary engines) and very tight, helpful community.
Development is as "high level" or "low level" as you prefer ... you can stick to basic Lua scripting (sort of like JavaScript) and create a full game without ever dabbling in the C++ and OpenGL side of things, but if you want to delve deeper, the option is always there.
It's not as "do-everything-for-you" as engines like Unity or GameMaker though, you will need to be able to code a bit and understand the fundamentals of the platforms you target.