Magnet Radius Spam
\Magnet Radius is too easy to spam to higher levels. As long as there's stars in your magentic field, you gain magnet xp. So, you just let lots of stars camp out in that area without catching them, and your magent xp level goes up to insane amounts.
I think the scoring on this game should be such where you're rewarded for AVOIDING XP. Reward the player for using the smallest magent/catch radius possible. Otherwise, folks can just spam the radiuses to insane amounts, create blackhole effects, and wipe game levels before they even start.