Dr. Brain: Action Reaction/Level 20-29

Level 20
This level introduces breaking turrets with balls. Note that not all turrets here shot rockets, some shoot balls instead. Use the attractor spheres to aim the ball turrets. Shot the turrets with the helper hand to make them shoot balls.

With the central turrets gone, just raise the bridge and walk over to the exit.

Level 21
Say hello to the rat maze. It will be difficult to find your way to the exit with all the tight corridors. The exit is also locked. Find your way underneath the maze to a chamber under the middle of the floor. There is a computer in the chamber, hit it with the helper hand to unlock the exit.

Level 22
Another portal maze. As before, there is a switch to unlock the exit door. Unlike before, the exit door is actually part of the maze.

Level 23
A repeat of level 9, but they changed the code. This time it's, from the left side, On, On, Off, Off, On.

Level 24
Another floating platform maze, but 2d this time. Oh, and the platforms move automatically.

Level 25
This level is about turrets and tight corridors. Use the rockets of the aiming turret to destroy the turrets shooting in fixed directions to clear the path forward.

Level 26
This level is a jumping challenge. There are several moving platforms in the area that you need to jump between.

Start by getting up to the red teleporter. Once up, follow the arrows on the floor as you drop down to the yellow teleporter. Look before you leap into it, since it leads to a moving platform that's not there most of the time.

Said platform leads to the green teleporter, again look before you leap. The green teleporter leads directly to the blue teleporter. Take the blue teleporter and follow the path to the exit door.

Level 27
A repeat of level 15, but now the bins move around. Just aim at the same spots as the previous time and mind the timing.

Level 28
Another gelevator maze. Look before you leap and mind the rocket turrets. As before, stand on Craven's face to unlock the exit door.

Level 29
A repeat of level 8, but this time the bins are on the "wrong" side. You will have to raise several pillars to guide robots to each bin.