Very glad you enjoyed! The cubes do make a sound when they spawn, but not when they move, nice suggestion. Waves of enemies would be great, also!
I assume that the graphics were lame, but I don't know much about shaders neither modelling. I'll promise that for the next jam I'll improve the graphics, haha.
About the theme: my focus were to keep it simple, and around the "shoot to kill the enemies!", but this didn't gave me much creativity and I didn't expanded much from that.
Thanks for playing, and for the feedback!