For some odd reason, the score that shows up on the level select is sometimes different from the one shown at the end of the level. It's happened twice to me so far: In level 7, the results said "A", but the level select showed "A+". Not a big deal, I figured, but in level 9, it said I got a "B" (even though I had 10, exactly par for that level, which usually gives me an "A"), and when I went to the level select, it said "A+". So apparently, if there's an error, it automatically defaults to "A+". It's nice that it does that, but I fear people can just glitch their way to total victory.
On the game itself, I thought it was fairly interesting, but when not going for the par score, there's not much of a challenge at all. Once you blacken tiles, they stay that way, which is a bit odd, since I thought I was casting shadows on the planet, not sucking the light out of it.
I really enjoy the concept behind the game, though. I would like to see future games from you incorporate terrestrial manipulation in the theme.