A great start! Both in terms of aesthetics and gameplay. So much potential, I hope you make a fully-fleged game out of this! I imagine being able to upgrade planet base, create planet defenses, ship specials and more. I still couldn't wrap my head around the fact that only one ship (or unit) is allowed to attack a planet at a given time. Why wouldn't it be possible to surround a planet and perform multiple attacks? Would also make defending a planet more interesting, I believe. Anyways, an awesome start!