The series takes place after RE4 but before RE6, so knowledge of RE2 and 4 is needed. Storywise the show is pretty mediocre and doesn't really add anything to the overall lore of the RE-Universe. The pacing is also all over the place because the show likes to switch not only between characters but also time, sometimes showing the same scene up to 3 times only to add another little bit onto it which becomes pretty tedious real fast.
Speaking of characters, the series brings back both Leon and Claire as the main characters, except that Claires plotline is completely unnecessary and she doesn't really do anything worthwhile. Even removing her from the story wouldn't change anything which is just really frustrating since all of the advertisement portrayed both Leon and Claire as equals, yet she again gets to do nothing like in Degeneration. The new characters also aren't anything to write home about. The asian girl is pretty bland and I already forgot her name, despite finishing the show like an hour ago. The main "bad guy" is pretty much the main character from Final Fantasy Origins who repeatedly screams CHAOS, except that this guy likes to say terror. I really couldn't take him serious. Leon on the other hand is awesome, though that mostly comes from him simply being Leon.
The Animation as a whole is pretty good, most of the time looking amazing and sometimes being pretty bad. It basically gets worse as the show goes on but never really becomes downright awful. I would say its simlply inconsistent. You can also recognize which characters are gonna appear more often than others because some character models reminded me of the old PS3 days.
Overall I would say that if you enjoyed the other CGI RE movies then you will probably get some enjoyment out of this. The show definitely could have been much better and I was really disappointed by it. It's pretty obvious that this was originally meant to be just another movie, that was then split into 4 parts to create a series and gather more hype since the previous movies didn't perform too well. Hopefully an eventual second season can fix some of the afore mentioned problems and thus turn out better in the end.
