In Wonderland, McBasilRocks indicates it is possible to get Oswald to come to the top mushroom and help get Mickey through the window of Alice's Wonderland House.
I have many saved games, and went through that Wonderland situation for hours. Dropping a clock or even jamming the doors, or trying to get the eye to watch TV didn't work. I tried dropping to the doorway from the roof. Once I made it through the shutters, and watched them close with me inside, then I reappeared in the middle of the yard. WHAT A FARCE!!!
I presume that later you can return to Wonderland and bomb the house to get the other projector, and use paint on the slobber in the fort to gain 16 films -- but, then, it seems impossible to do the DEC between Floatland and the Fort, because there is a wooden doorway in the way, that only gets raised from the other side. I even went to the fort to see if I could bomb the rock wall that falls if you use thinner -- no luck.
QUESTION: Has anybody actually been able to get the challenges for all 5 DECs and 16 films in one game slot?
I have many saved games and spent a lot of time going over the possibilities.