10 for cool concept
The gameplay turns out really repetitive and there aren't really any options.
I'd add in distance and power to your throws, and have different planets of different sizes. Also the dudes finger blocking the rock is a good touch but it really happens too low and it destroys any kind of momentum your meteor had (sometimes if something is near the top of it's arc and the finger touches it, it just drops straight down doing nothing).
The UFO needs to be touched up it seems to bounce depending on what side hits the ground/object. I've thrown it at full angle at empty ground and it's bounced far enough to have the finger push it back, but I did the same thing next round and it bounced up slightly in the same spot and dropped, doing absolutely nothing.
Make different planets! You shouldn't just see how much damage you can do to the same planet over and over, you should be able to see how much damage you can do across the galaxy. Different alien planets will have differing gravities and compositions. By compositions I mean like some could have caves that crumble on top if you hit it ending your meteors destruction, some would have metal deposits near the surface that bounce things away more. Also make craters where the meteor/moon/etc hit and composition would affect crater size and how much momentum the object would keep.
Keep up the good work you could polish this into a gem.