My familiar looks for a movie, which i watched somewhere in 2011 , a kid entered a door and he was taken to a different parallel universe where he was captured by some kids his age that lived in a jungle in a small castle thing , they later became his friends and the real enemies were the government who caught those kids and put them in a machine and turned them into grown men to fight for the government . ( sort of like in the avengers where captain America was transformed into a muscular man only they were transformed into grown men from children ) The government also had an arena where they put enemies there like the children , and they had to fight this huge metal circle ball robot with tentacles . Later in the movie the protagonist ( the kid ) finds the control room of the robot and destroys their arena or their city i think . In the end he returns to the real world and cries, because nobody believes him in what happened.
Other scene: the protagonist ( the boy ) found a big egg on the ground and helped to put it in its nest on a tall mountain where and turns out the egg belonged to some sort of phoenix big bird.
Any interesting idea?