I’ve tried lots of game engines during my, like, 4 or so game jams (most I couldn’t finish). I think ct.js is the easiest, and GDevelop is maybe almost tied with it but has more features. (Both use a bit of JS, but no big deal.) The easiest language is MiniScript for the MiniMicro (or the English-like scripting language for Inform7 is a close second).
I recommend to follow a tutorial for whatever game engine. Then, replace the graphics from the tutorial and start customizing it a bit here and there. That will get you through.
Of course, the no-violence thing might be tough. You could put squirt guns or paintball or something in place of the violence in other demos and tutorials.