We have no problem with artistic license in a Bible-themed movie when it is done properly. In fact, anytime you decide to depict historical events, you will be using artistic license. The difference is that the filmmakers went beyond artistic license when they overtly contradicted the text in multiple areas and completely changed the character of Noah from being a godly, righteous man into a madman who was bent on making sure every last human being died, even if it meant Noah must slaughter his own grandchildren. See Paramount’s Noah: Artistic License Run Amok for more details on the film’s abuse of artistic license.
There is no doubt that this film will provide an opportunity for Christians to talk to people about the film. But talking about the film and connecting the ideas to the truths of Scripture is actually going to take a lot of work. How will you explain the film’s “rock people” from the Bible? Why doesn’t God speak to Noah in the movie? Does the serpent’s skin really give magical powers? Because of the multiplicity of errors and the paucity of biblical truth, sitting down with an open Bible and deprogramming the person who saw the film is the only answer—but it is going to be a lot of work. It would be a lot easier to encourage someone not to see the film and then offer to teach them the true account of Noah.
Ultimately, if we are looking to an atheist to make a film that that provides us an evangelistic opportunity, then maybe we have forgotten something: the power of the proclamation of the gospel (Romans 1:16–17) and the command to preach that gospel—even when there isn’t a movie to help us. With that said, there are still going to be opportunities to talk to those who have already seen the movie, but Christians are going to have to be intentional and boldly speak of the truth of God’s Word with words of grace and truth.