I want something that's open enough that I can make any type of game or mechanics with it (although I am focused more on 2D puzzle and turn-based strategy games).
Unity seems to be overkill but I do have experience with it, and I used to churn out Flash games a decade ago. Now I'd like to update a few of them to HTML 5 and bang out a few other ideas, but I have much less time to work on them than I used to back in the day.
Something that could be translated to a mobile app without much difficulty would be nice, also, like 2048 was.