This film serves plainly as a prequel to the game, as described above. There is little to be discovered about plot tied to the game. I was hoping we may find out something about the original 'Red Marker', but unfortunately this was not covered. The only new thing I learned from watching this film was exactly how the alien creatures managed to board the USG Ishimura.
The story follows a small security group trying to halt the attacks on the USG Ishimura from a strange alien race that has the ability to revive the dead, turning them into violent and mindless creatures, similar to the game. There are also a few sub-plots detailing the unitologists interest in the Black Marker. Characterisation is weak, using very stereotypical roles to fill out the cast. You pretty much know exactly who is going to live or die as soon as you are introduced to them. Script is also bland, with a hefty use of familiar one-liners. Swearing is used a disproportionate amount, failing in it's aim to create a more adult dialogue.
I have not researched the animation's production team, but the style is very similar to that of children's and young teen's cartoons, such as Avatar, Jackie Chan, etc. A kind of American anime, if you will. Being given a more adult storyline has not really inspired the team to go all out. Gore was less than satisfying (considering this was a main point of sale) and animation was generally cheap and unprofessional.
So, in conclusion, this is worth watching purely to see what happens a short time before the game, all of which you can find out from the game's own collectable audio and text logs. I really do not recommend buying this title, even if you are a fan of the game.