Whats that video game...?

Ok so the movie is about a boy and his dog gets stolen i cant remember how. And he ventures off in some fantasy land to find his dog. In the beginning of the game in a cutseen he gets in trouble at school and the teacher puts him in a closet. Then he goes home and goes up to a tree house where he made this like spaceship type thing to travel. If i can remember the things he has to fight are like these shadows. It was for the PS1.