Questions & Answers about Acho que o filme é bom.
Why use acho here instead of penso for "I think"?
In Portuguese, achar is used when expressing an opinion or a guess. Pensar is used for the actual mental process of thinking. Since you are giving your opinion about the film, acho is the natural choice!
Can I leave out que like we drop "that" in English?
Why do we use é (from the verb ser) instead of está (from the verb estar)?
We use ser (é) because you are describing an inherent, permanent quality of the film. If you used estar (está), it would imply a temporary state, like saying a hot meal is good right now but might get cold later.