Algodance is an activity that introduces algorithms for middle school children by making them dance! I was the designer of this activity when I worked at Dragonbox.
In AlgoDance, children can choose instructions, place them to create an algorithm and then execute it. The character in the center of the screen does the moves, but the goal is for the kids to do the moves as well. It is possible to hide the character so that children can only rely on the instructions. We have created different levels that include new concepts. Students will discover instructions, loops, conditions and even variables. This last concept is the most difficult to teach. Most of the games that introduce coding to children do not cover variables (or they say they cover it but actually teach parameters, which is very different). However, we thought it was a major concept, so it is good that students can be introduced to it as soon as possible.
It's not exactly a game because there is no objective, it is a sandbox where children explore and test different algorithms. It was designed for Norwegian middle schools and it is not the only activity we imagined to teach algorithms. Other activities are more suitable for practice and assessment, which is why we decided to keep AlgoDance as a sandbox.