I feel sad now because if I tried this game when I was 8, I would have aced it. I was really into geography back then. I'm 17 now and I barely scraped the medium badge with a miracle strike at just the right time.
Okay: here are my lists of general hints for the game since so many people just ask without trying to figure it out:
1) If the enemy has a buff to do massive damage or healing, get a debuff skill.
2) If the enemy heals for a massive amount, use Subversion. Watch the HP meter, and find out at what % they heal.
3) If the enemy has a crapton of health, just keep fighting it. A way to win will pop up.
With these, you should be able to handle most fights in Sonny 2, even on Heroic.
The worst part about this game is that it's the last one. 5/5. And if you don't like grinding, get better at it. You may have to do some grinding but the more skill you have the less grinding you have to do.
Killers? Memorizing those little tiny islands is probably the only way to get a strike on such a small map. The strike should be within 15 km or something...
The secret way to get the medium badge is to first get 5 stars on the first five levels before the boss, then defeat the secret mission that appears on the screen.
The reason Xeno Tactic was good was because it was just a clone of Desktop Tower Defence. Now they've at least tried to branch off on their own, cut them some slack.
Admittedly, this is a difficult game, but it's not the hardest I've ever played. People who are currently having macabre visions of smashing their keyboard with any heavy object that comes to hand should certainly avoid I Wanna Be The Guy. This isn't platforming hell. This is easier than I Wanna Be The Guy. I'm going to get through this, and so can you.
People: Barack Obama did not endorse this game, Ivory put it in there as a joke, probably not expecting anybody to actually fall for it. I repeat. It. Is. A. Joke.
The campaign mode badge has not, in fact, been fixed. The spartan one has the same problem, but I legitimately earned that one anyway. I'm going to try to earn the campaign badge properly, but just so you know, I earned it through the glitch, so it's not fixed yet.
 "Bible Fight"){kind=icon}
 "Globetrotter XL"){kind=icon}
 "Draw-Play 3"){kind=icon}
 "Sonny 2"){kind=icon}
 "Protector III"){kind=icon}
 "The Worst Game On Kongregate"){kind=icon}
 "Cell Warfare"){kind=icon}
 "Divine Generals"){kind=icon}
 "Balloon Invasion"){kind=icon}
 "Xeno tactic 2"){kind=icon}
 "Meat Boy (map pack)"){kind=icon}
 "Storm the House 3"){kind=icon}
 "Hanna in a Choppa"){kind=icon}
 "Bloons Tower Defense 3"){kind=icon}