Thank you for the input, everyone!
I didn't even think of mentioning spoilers until Tony mentioned them - by its nature, this thread will be spoiler-heavy, and I should have mentioned it in the original post and will add it if I can still edit it. If not, then it doesn't get any less spoiler-ific from here, sorry for anyone who hasn't seen some of these films!
On the plus side, I kind of liked things like that haunting black lake, and the white void near the beginning of the film, and the enigmatic introduction with bright lights and strange shapes floating in dark voids, the background music was fairly unearthly and the minimalist film-making was fairly disorienting. In a way, the various human characters were enough of a cipher compared to the development we were given to the alien that the human characters seemed more alien than the alien did.
But, in the end, I just couldn't think of any way to put the pieces together and get a Lovecraftian theme out of it, without it feeling like a stretch.
If I were to include this in a list of "Lovecraftian" films based on that alone, I'd feel obligated to add "The Man Who Fell to Earth" and "2001: A Space Odyssey", and although I think I might be able to spin a halfway convincing case for "2001...", there's a certain point beyond which only madness lay, and I'm skating too close to that point already with some of the film suggestions I have been including.
But, I'll leave the question open in case someone saw a subtle but convincing connection that I missed (which is entirely possible).
"Species" was a good comparison, actually, and strangely I didn't have that film on my "to do" list yet because I didn't think of it myself and none of the lists I used suggested it. However, I can understand and get behind "Species" as a suggestion - beyond just the tentacles, as mentioned by eternalchampion the monster there was suitably indifferent to humanity beyond its value as Human Resources, there's the H.R. Giger character/set designs and special effects (from his Necronomicon art series/books, if I remember correctly), the way the alien was assembled in a lab with instructions from another world or another dimension which could be described as a sort of "piecing together of dissociated knowledge" opening up "terrifying vistas of reality" or in terms of an unearthly monster conjured up after delving too deeply into a sort of electronic or genetic forbidden tome, and from what I remember of the film and its sequels it had a sort of ready-made Delta Green plot to it with a cell of agents from various organizations trying to track the monster down before it's too late....
Edited by yronimoswhateley, 06 October 2016 - 12:51 PM.