My 9-year-old son Gavin designed the game below on the site www.gamestarmechanic.com. (Thanks to @bradfordgs for leading us to this.)
Gavin has had a lot of fun playing the games on the site, learning about the nuances within a good video game, and then designing and trying out his own. He is now to the point where he is soliciting feedback on his games in an effort to make his games better and more interesting.
Gavin wants me to share that the “game of cool” he has built below has 5 levels, it is really hard, but really fun. He says, “Keep trying until you win it.”