Complex sentence: Custer's fatal tactics at the Little Bighorn were far more complex than portrayed in the film, which portrays him as having a searing hatred of Indians and as acting ruthless towards them in battle.
Split into simpler sentences: Custer's fatal tactics at Little Bighorn were far more complex than portrayed in the film. The film portrays Custer as having a searing hatred of Indians and as acting ruthless towards them in battle.