It's very hard to make Breakout clones imo. To stand out, you really need to have super feedbacks, neat visuals and a very creative concept and/or universe if possible. Good examples are games like Nervous Brickdown, or Shatter, that really are the last great games of this genre from (my) recent memory. Your game clearly lacks feedbacks, comprehensive physics, sounds and thematic visuals to be enjoyable sadly. But it's not the most important, it's really things that you can improve or add from now on.
Your concept is the main topic. I think having planets in place of balls is a cool idea, and could be really reinforced by a space thematic: asteroids in place of blocks, stars in the background etc.. But let's talk about the gameplay. The issue is that games don't really feel different when I chose other planets. It's just more and more confused as I select more and more planets. There's a balance problem: some planets are too fast, or the paddle is too slow.. the space between the 2 sides is too small too. Some tunings that can easily be tweaked. The abilities of planets don't feel different either, it's more like characteristics: big/small, fast/slow.. except from the missiles which are a clever idea.
Anyway.. there are lots of things still to be said, to improve, but I guess I made a general point. I know it's not something you (nor me) want to read but imo best things about game jams are pushing the limits and sharing constructive criticisms (and having a good time of course). So well done for trying out this idea and good luck for the next one!
PS: if you need sounds, Bfxr.net is really the savior of game jams. Easy to use and quite powerful for a navigator tool.