Being a sole developer I find it quite difficult to develop for multiple platforms at the same time unless there's a framework that allows me to do so. Are the people behind the games in the bundle using a sort of "multiplatform-framework" ?
That said, writing games is one of the hardest types of software engineering task, in my experience. On top of that, all but the best games tend to have a very short lifespan compared to other kinds of software.
You've really got to love making games to stick around in the field long enough to get good.
"Apportable is a venture-backed team of six engineers, looking for a few more. We're solving some ridiculously hard problems porting iOS to Android. Our software is already being used by some of the world's largest and best game developers"
As of at least a year or two ago Qt as been LGPLv2 and thus you can write proprietary software with the free Qt license as well. The only thing you can't do (without releasing your code) is make changes to Qt itself.
Which is to say; make a game with compelling and interesting rules that doesn't rely on performance