Help finding a movie

I watched it somewhere in 2011 - 2012 , a kid entered a door and he was taken to a different parallel universe of sorts ,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 his mom finds him, and cries because nobody believes him in what happened . I also remember a phoenix type bird in the movie living on a hill with eggs , the kid helped bring an egg back to its nest because it fell .

some FACTS.
1 ) I do not remember what language the movie was in i am assuming English .
2 ) I do not remember any actors
3 ) This was not an anime , cartoon or anything like that .

Also it's not Narnia or Maze Runner

Forever grateful to whoever helps me locate this nostalgic gem of mine.