In particular Boyce Davies feels the film underplays black resistance to enslavement. She writes in her piece for The Guardian that the narrative of escape and engaging actively against slavery are prominent in the book:
Northup indicates that not a day passed without him contemplating escape. References to the Great Pine woods are a constant symbolic evocation of the possibilities for living elsewhere than on the plantation. The journey between that “free” space and the plantation marks the boundaries between being free and being enslaved. Northup chooses the plantation, and in the end attempts to secure his freedom the “legal” way in a context where the illegality of slavery itself was in question.
You can read Carole Boyce Davies’ piece on the film and book here: