The red dice moves once every 2 turns. There is another enemy type in level 4 to 6 : a blue dice that moves once every turn.
I thought it added some kind of difficulty curve and some enemy variety.
About the dice-touching mechanic, it's something I briefly explained in the description of the game, but I don't think I did a good job conveying that it was the goal of the game. It's not the most intuitive mechanic unfortunately, and that is why I realized it's important to convey this kind of information with gameplay by forcing the mechanic to happen in-game, for players to learn with experience.
Thanks for taking the time to play my game!