This is a pretty cool concept. I especially liked the planet physics which makes the game really satisfying. The gameplay could use some more explanation, didn't realize I had to gain more mass than my neighbor to win. You could also display the neighbor black hole's mass so that the player gets scared when the mass of the neighbor black hole is close to being above the mass of the player's black hole. Also shooting planets at the black hole can be difficult because I'm not sure where the black hole will be (although this is a minor issue). Maybe add a curved arrow from the black hole that matches with the arrow coming from the planets. Overall cool concept! Also liked the SFX.