This is a film about the importance of imagination and allowing yourself to keep dreaming, and its terrible special-effects only drive its message home more. Look past what's external and factual and allow yourself to be taken away to Fantasia.
Those who complain about the imaginary beings being unbelievable are obviously missing the point of the story, our perception creates reality!
If you decide they are unbelievable/ridiculous/corny - they are. If you choose to be inspired - you will be.
Will the imaginative child in you win or the logical, critical adult? The choice is yours.
The story is simplistic and the acting could be better but overall this is an amazing film that, if you allow it, will deeply move and inspire you