Hey there!
I just finished playing Puzzle Bots, and while the starter of this thread probably figured out the last puzzle months ago I thought I'd post a little guide for anyone else who struggles:
Puzzle Bots 'Final Boss' Puzzle:
N.B: The key to this puzzle is to use all the bots' abilities in the correct order and apply a bit of physics.
1. Control Bomchelle. Note that between Zander and Yuri's heads is a weak link in the chain holding them prisoner. You may attempt to bomb it, but your bomb will fall short (and hurt Zander's shoulder in the process).
2. Control Ibi. Roll over to the puddle below the shelf and tow the lid on the grate to enter a two-way pipe. The right pipe will lead you to a grate blocked by a toy soldier and a clump of gunk. Tow the toy soldier out of the pipe and onto land.
3. Control Hero. Pick up the gag that was on Zander's mouth and use it on the toy soldier to form a sort of parachute. Observe his 'fragile' gun and snap it off.
4. Control Ibi again. Tow the gunk to the opposite side of the pipe to lower the water level.
5. Control Kelvin. Move him into the pipe.
6. Control Ultrabot. Push the grate opening shut.
7. Control Hero. Place the parachute/soldier on the shut grate.
8. Control Kelvin again. Flame the bubbles.
The soldier's parachute will be inflated and it shall rise, landing on the weak link.
9. Control Bombchelle. Bomb the solider.
Note: You shall have to control Ibi every so often to prevent the gunk from flowing back into the right grate.
Good luck! Enjoy the cut scene.