The first 13 episodes are a great TV show, and achieves the “Shoujo for boys” idea that was being bandied around at the time. It switches between being essentially a shoujo story show set in school and the British telefantasy & 80/90’s Hong Kong movie-inspired action of the Read or Die OAV. Episodes like They Shout and In A Grove could have had their plots ripped out of The Avengers and are all the better for it.
Those 13 episodes end on a superb rescue sequence and had it stopped there we’d probably be talking about it as being one of the great series of the decade.
However then the fans of the OAV and light novels got what they had been complaining about being missing from the those 13 episodes and, possibly coincidentally, the whole production went to hell. As broadcast those final 13 episodes were just a mess. While the production problems were fixed for DVD release, the writing, which had been exceptional up to then, was in just as much a mess as the animation, bogged down in exposition and characters on the run for much the time.
An ambiguous final scene (was that dog supposed to represent a Churchillian depression or a creature like Black Shuck?) suggested more was to come, but given the loose continuity between the various ROD projects I’m not sure if they were hoping for a follow up anime or if it was picked up in the light novels.