From a gameplay perspective this is solid. However it doesn't seem to have much of an identity at the moment. I don't know how a cube jumping has anything to do with the themes. I'm sure you plan to add that later but at the moment it is lacking. Also the explanation how double jump was a bit awkward since I couldn't see all of the word double. So the word will need to be shrunk or made more visible to the player for that to work as an explanation.