Stencyl is a free game-making software tool designed for 2-D game creation. It's made primarily to operate in Windows, but it can plausibly operate in most Operating Systems.
That said, it doesn't get along well with various forms of Linux. That's why I, personally, have left it on the wayside.
Stencyl's system of "place the pieces" coding is relatively easy to understand and allows new users to fool around and find out. The tutorials are relatively easy to understand and the community is ready and willing to help even a fumbling dummins like myself.
Alas, it has bugs that are non-compatible with my timeline and OS, but I did help find them so maybe that's on me.