Haiyoru! Nyraru-ani is the heartwarming story of the loli personification of Nyarlathotep (Nyarlko) who is a by-the-books otaku wish fulfillment nerdy chick, who is in love with a normal guy called Mahiro who can only keep this non-tentacled horror under control with a hastily brought down fork slammed right throough her hand. Also; later in the series, we meet Cthuhko, who is the Japanese loli imagining of Cthulhu. And rather than looking like an octupus god like figure from the sunken sity of Rl'yeh, she is actually a kuudere girl who wants to feast upon Nyarlko's carpet.
So, that is basically the story and the character section rolled into one. I won't tell you what I think of what I just wrote, because due to whether or not you are a Cthulhu mythos fan or not this could sound like the worst/best thing ever written by mankind.
The next thing to talk about is the art, which is as far as anime art goes is quite bland and ugly, and the animation is rather low quality. However, I can be a bit more forgiving here due to the fact this was made with Flash, a program in which I can barely get a stick figure to move it's legs.
The sound was decent. The few VAs there were had done somewhat well known characters (Yuno from Hidamari Sketch, Harumi from SZS) and the ending theme after each and every segment was nice, whilst somewhat annoying if you are watching the whole thing from back to front.
I enjoyed myself quite a bit, in no short thanks due to the constant stream of Lovecraftian/Anime and Manga references they popped in at opportune spots. And whilst I realize this was nothing but an advertisement for a novel I will never see translated in my life time (and screw learning Japanese, Spanish is hard enough) I can say that it certainly amused me for its short run time.
All in all, I recommend this series if you are a Lovecraft fan. Partly because you may find the show's humour enjoyable, and partly because I might derive morbid entertainment from your screams of terror as you list down everything that this anime just raped about your beloved Mythos. Non-Lovecraft readers might enjoy it as well, just don't expect to know what the hell is going on half the time. I rate it 7 grave rolls out of 10.