Read most of the comics years ago, but only recently have I read "Hunger". One thing that was apparent to me ever since opening the books was just how much inspiration the author drew from Lovecraft. "Hunger" seems to take it to another level.
The most obvious parallel is to "The Dunwich Horror". It is about a family called the Whateleys; 2 major members of which were albinos (like Whately). Wilbur Whateley had an unknown father, though later it's revealed his father was the extradimensional elder god Yog-Sothoth. Whateley's role was to take the necessary steps to bring his father into this world. Yog-Sothoth himself would act as a gate once here, allowing the others of his kind to enter our world as well. This is pretty much exactly what Whately is trying to do in the comics; bring Samael into this world so that s/he can open the way for the other gods.
The second biggest inspiration seems to be "The Shadow Over Innsmouth". This story is about a quiet New England town in which the residents secretly worship an ancient god called Dagon. The townspeople slowly begin changing, becoming less human and more like monsters.
Less connected would seem to be a passage from "The Call of Cthulhu", which states that once the Great Old Ones (another group of god-like beings) are released from their bonds, they will teach mankind new ways to shout and kill. There are also several monsters that resemble Cthulhu's bulbous body and squid face in the comics.
There also are links to Stephen King's Needful Things, and to John Carpenter's film In the Mouth of Madness. Both of these authors themselves had been inspired by the works of Lovecraft.
Despite being a fan of Lovecraft, it's actually the heavy Lovecraft inspiration that turns me off of the comics. Silent Hill has always had its own unique brand of horror. Trying to make this brand of horror into another sullies the nature of the SH universe. Plus, Lovecraft is already one of the most imitated horror writers around (mostly by American and to a lesser extent European authors); and most of the imitations fail miserably. Good thing I have to say about Scott Ciencin is he at least is not one of the ones that tries to deny the Lovecraft influence, placing clear references to him in some places.