OK, first off, if you're not into Lovecraft or the Cthulhu Mythos, you won't get all of the references and jokes, but that's not to say you won't have fun with this movie. Underneath its rough exterior lies a film with plenty of wit and charm, and a "deep" (pun intended) love of all things Lovecraft.
The delivery, as said, is a bit rough, but after only a short period I found myself easily forgiving any of the film's minor shortcomings. No expensive, top-of-the-line special effects, an excess of foul language that probably should have been scaled (ha!) back a bit, and a couple of performances that weren't anything said performers would want to put on their demo reel (read: stiff).
Still, those things aside, the story is fun and silly, and maintains a nice balance between the humor and drama, avoiding any awkward or jarring transitional moments between scenes (if nothing else could be said, at least take note of that element, which I found refreshing, as I've seen quite a few "blockbusters" of late that failed at it, unable to decide whether they're action or comedy vehicles).
A somewhat imperfect analogy would be to reference the TV series "Chuck." Take any old Lovecraftian Hammer film and drop Chuck & Morgan down in the middle of it as the protagonists and you've got a good idea of what I believe this movie was intended to be. I wouldn't go so far as to say it completely succeeded, but in the end I think it worked well enough to make the movie enjoyable.
Ultimately it's a light-hearted Cthulhu Mythos comic book on film, with nods to geeks, gamers and Lovecraft fans everywhere. Will it necessarily be everyone's cup of tea? Nah. What movie is? But if you're in the target audience, and can go into it with a smile on your face and no Cameronesque expectations, there's a good chance you'll have a good time and even find yourself later talking about it with friends over your Mt. Dew and Funyuns as you prepare to toss the percentiles and hope your character doesn't go insane.
