Well that's definitely not my style of game. I did complete the level with B and just to prove that I could, I also managed to tap the win with the free-draggable. If I were to rate this level, I would give it 1 star for having an appropriate title. But that wouldn't be fair as it was clearly not designed for me and my preferences. Based on what I can assume were your intentions, I think you succeeded; I just don't know how to put myself into a child's shoes and rate it from that perspective. Just be aware that free-draggables - even those anchored as you did here - can be unwieldy and can lead to unexpected results. As a consequence, pretty much everyone avoids designing with them. The obvious alternative would be to attach them to a slider or motor. Alternatively, if you want a non-draggable but still moveable block, we found that you can attach metal blocks to a motor that is free of attachments, i.e. it's axle is not connected to any external object. With that, welcome to the forum! And thanks for the nice upload!
@Mse&Csani - Try @richardfu_'s Castle Jump. Maybe a little hard for a five y/o, but he'll probably like it. And I hope it will inspire you both try to build something somewhere in between in terms of sophistication.