Anyways, since I know that you came here for the solutions to the mind numbing puzzles this game has. So here is Humbug 2 guide demonstrating how to beat the game.
Where and how to find the hidden items in Humbug 2 written guide:
There is a gem that can be found on the menu screen. Just above the poster there is an arrow drawn on the brick wall. Click the brick to the very right of the arrow tip a bunch of times until the blue diamond falls off.
On stage 4, go to the vending machine and key in the following code: 5369. After you enter the code press space to interact with the area where it says 'unlocked'.
On stage 6, you must have the pole-ax and walk in exact time with the knights. I repeat, in the very exact time with the knights.
In stage 8, when you are floating up using the balloon turn your power to zero in order to receive the harp. When you reach the angel you will need to put your power back up so you live once more and take the harp. Restart the level to get out of the scene.
On stage 12, after you pull the brick out from the turret quickly press Q to pause. Then place the brick so you can jump on it and pull out another brick from the turret. Your objective is to climb to the top of the level and get the white diamond from the cloud hanging on the far right.
On level 13, you must pause the game just when the bridge has been drawn halfway. Then climb halfway up the clock-tower to jump onto the bridge and get the bat. You can then press Q again to resume the game so you may proceed.
On level 16, at the very beginning of the level, jump up and down eight times in a row. You must do this at the very start of the level.
That's all folks. Also see Humbug walkthrough, the original version which is equally challenging as this one.