The 90s horror anthology Necronomicon is my favorite HP Lovecraft adaptation.
That and In The Mouth of Madness (which was only inspired by Lovecraft) were genuinely scary films, a breath of fresh air during the self-aware slasher boom.
It's all about the last segment. The opening segment has a great atmosphere and is the most tentacle-y, the middle is just so-so-, but the end, man, it was messed up.