It's a nice concept but I feel like the mouse control could use a dead zone so if the cursor is close enough to the player he'll stop following it so you can actually shoot without slowly drifting toward your cursor as the closer you are to it the bigger the angle of shooting change for the same distance mouse travels, also it would be nice if there was a small breather between waves so you have a chance to catch your breath and reposition. Also it's almost impossible to realize that it's a game about space I actually needed to check "How does your game fit the theme" to notice I feel like something like particles or a scrolling perlin noise texture with high cutoff could have created some nice stars so you could actually connect the game with the theme.