1. The Plot Holes. Oh God, The Plot Holes
Forget the Alien continuity. Forget the visual design that doesn't fit. Forget the bad acting. Hell, even forget the pointless characters. This is what makes Prometheus a terrible film; its plot. It's lazy, half-assed, badly put together plot. Nothing in this film adds up. You could say they are saving it for the sequel, but...sorry, no. If I spend two hours watching your movie, you can't say, "sorry, you'll have to wait three years to find out half the stuff in this movie actually happened!" There are too many plot holes to list here, but here's a few of my favourites: Why did Fifield get lost when he had the map on his arm the whole time? Why did David spike Holloway's drink if he has no emotions? Why did they pretend Weyland was dead the whole time? How did the Engineer know where Shaw was in the climax? Why did Shaw and Vickers run in a straight line away from the giant ship rolling towards when literally any other direction except backwards would have been better? How did Shaw not feel immense amounts of excruciating pain when she was running and jumping everywhere? Why was there a shrine to a fully grown Xenomorph in the cave when the ending clearly showed us a 'proto-xenomorph' coming out of the engineer's corpse? These are just a few of the plot holes. I can't list them all here - I don't have enough time or space and I can't remember every one - but trust me there are more. If you want a really in-depth analysis of all the things wrong with Prometheus, check out
Film Brain's review on Blip TV. Well worth a watch. Well, that's my take on it. If you disagree (and I know a lot of people will), feel free to say so in the comments.