good early strategy (for first few levels): keep spawning arrows until you get enough mana and start spamming archers, when they start approaching the castle Super Spam Hobbits to distract any archers or swordsmen.
For 5-2 you just (If you want to get A):
1. You get the first two acorns.
2. then you kill yourself in the little pit.
3. Then you go up get the red key, and stay in the cart.
4. Just jump up and get the normal and gold acorns.
 "Doodle Devil"){kind=icon}
 "My Pet Protector"){kind=icon}
 "Alice is Dead - Ep 1"){kind=icon}
 "Toss the Turtle"){kind=icon}
 "GeoSketch"){kind=icon}
 "Bash Your PC aka MÉTELE AL ORDENATA"){kind=icon}
 "Death Dice Overdose"){kind=icon}
 "Hands of War"){kind=icon}
 "Achievement Unlocked"){kind=icon}
 "Epic War 2"){kind=icon}
 "Punk-o-matic"){kind=icon}
 "entangled"){kind=icon}
 "SeppuKuties"){kind=icon}
 "Monsters' Den: Book of Dread"){kind=icon}
 "99 Bricks"){kind=icon}
 "Interactive Buddy"){kind=icon}