What I like:<p>* block-based, similar to Scratch.<p>* while some people want option for direct text input, I like the blocks, as it is less intimidating for beginners.<p>* I genuinely learned few things that I would not have bothered to learn otherwise. I would recommend it for anyone who wants to go beyond simple shell commands.<p>What I don't like:<p>* it already assumes that user knows some of these commands. There isn't any instruction on the commands, except for a brief example shown when hovering on top of block.<p>* there's no help or clue so if you get stuck, it requires a little bit of googling. For example, I had no idea how to convert uppercase to lowercase. I had to use Google to find it.<p>* One challenge (`belle`) assumes that user will have knowledge of Chess notation or learn it on the spot, which offers more info on chess than on the actual topic of unix commands. I could imagine a user who has never played Chess to spend at least couple of hours trying to understand what is going on.