A really cool idea with some nice hard choices for the player (R is necessary but also takes on a big risk as you lose your guns). I like that you can choose how to position the guns, and you can accidentally blow up gun asteroids, adding a "don't shoot the civilians" aspect.
I didn't really get a sense of the game fitting the theme of "scale" - hitting R didn't feel like I was growing bigger, it just filled up a blue bar. I'd like to see the growing actually adding slots for more guns and asteroids, but also making you a bigger target. (If that is in the game, it wasn't really noticeable.)
Also some animations to show what R is doing would help - initially I was confused what R was doing and thought it was just restarting the game.