Simple reaction game where you have to respond to the next color and navigate to it. It is a good starting point with grid movement and checking collisions if you are on a certain grid tile or not.
I like the randomly placed and ordered colors to keep each run different. The movement can feel a bit delayed? I don't know if that's the browser or how it was implemented.
I would maybe add a penalty to going to the wrong color to add an additional challenge or even have changes to the environment like removing tiles or making them more dangerous?