Neat, but buggy. The size of the goal regions depends on the level of zoom I'm using in Chrome. Up through level 6 playing with 175% zoom is fine, but level 7 is unbeatable in that state and I need to reload the game. When I first tried it all of the planets were sitting outside of the circles and there would be no way to force them in. It wasn't until I saw the walkthrough and could see from the drastically different sizes you had compared to me that I could realize that the game was unsolvable from that state.
If I instead start the game very zoomed out, level 7 automatically passes, no links required.