Cool
It's quite cool and the physics are smooth and nice, I like the idea of the magnets, but the levels lack interestingness and challenge, they only have seemingly randomly placed magnets and you just have to shoot randomly and hope to win!
I find it really stupid though that you can hit the alien, win, and then the ball can bounce back and hit your guy as well, and at that point you will lose. However, if you're fast enough and click on "Next Level" immediately as it appears, then you can avoid losing like that... I think that's a bug to fix!