Meet Amazing Alex - a creative kid who likes to make barmy contraptions out of toys and other things he finds lying about the house. In this physics-puzzler, it's your job to slot in the missing pieces to make his chain reactions come to life.
The fourth chapter is The Treehouse. These 32 stages take place in Alex's backyard getaway, and introduce a few new toys. We get to play with the bouncy ball, the remote control helicopter, and the zip wire.
If you get stuck, load up the level fresh and then recreate the setups shown in our screenshot walkthroughs. If you follow our advice to the letter, you'll beat the stage and unlock three stars on every level.
Level 1 - Angry Bird

Level 2 - Giant Drop

Level 3 - The Evil Dr. Pig

Level 4 - Chopper Pilot

Level 5 - Chopper Rescue

Level 6 - Alarm!

Level 7 - Ball Boy

Level 8 - Bellhop

Level 9 - The Great Escape

Level 10 - Barking Dog

Level 11 - Bellyful of Coins

Level 12 - Ski Lift Sabotage

Level 13 - Pirate's Puzzle

Level 14 - High Jump

Level 15 - Drag & Drop

Level 16 - Skatepark

Level 17 - Alien Escape

Level 18 - Boing!

Level 19 - Quantum of Mayhem

Level 20 - The Dog Returns

Level 21 - Bullseye!

Level 22 - Refueled

Level 23 - Mrs. Doll I Presume

Level 24 - Pinball Machine

Level 25 - Particle Accelerator

Level 26 - The Ride Home

Level 27 - Underworld

Level 28 - Valet Parking

Level 29 - Storm the Castle

Level 30 - Oil Pipes

Level 31 - Safe Landing

Level 32 - Free Them All