If you haven't watched Alien: Covenant already, then don't read further because of some major spoilers.

Wow! Fassbender stole every scene he took part in! Mainly as the android David, but also did a great job as the dutiful and obedient Walter.

I think his character is really unique because I can't think of any other film that has an android kill 1000s of intelligent life-forms all in one go, as well as playing a sadistic game with the survivors and then at the end basically given the chance to 'experiment' with another 1000 organisms. He's one of the most cruel and psychotic characters of all time, if you think about it. Fassbender makes you believe his (David's) motivations and there are some nice moments when he shines brightest; e.g. the facehugger scene in his cave and also the end when he just stares at Daniels - relishing her pithy attempt to escape certain death in the future.

So anyway, after this film, I can't ever look at him the same way (as an actor) as I had before - he is David. Like how RDJ is Iron Man or Ford is Indiana Jones