Okay, i might have a couple of suggestions that could make Illumination into a better game.
1. need to tie in some of the Cthulhu mythos with the enemies. Looking at the HP Lovecraft wiki and i keep on seeing plenty of disturbing shapeless masses, including lots of eyes and mouths and drippy tentacles and all other shapes. The only thing that ties that mythos (besides the big bad god himself) was the Wraith/gaunt (wingless type though). the developers could simply have a look at the original game: it had nightgaunts, zombies, and Deep Ones (and even a Cthonian, but maybe make that a common enemy)
2. Make it less Mundane.
From what I can make out from the Youtube videos, the missions just involved trying to find a power battery for a so-called generator or a key to a door. How about having some interactive stuff besides shooting stuff. Resident Evil made environment that had puzzles, even original Alone in the Dark had plenty.
3. Make it not about action, but of horror and suspense, don't have loads of monsters.
4. Other stuff. Make final final boss more of a insidious threat and a more Great Old One like presence than just absorb a certain amount of bullets, he's ancient and malevolent god, for goodness sake.
5. Maybe reveal what actually happened to the villagers of Noriwch (were they abducted, etc.) or a person being grabbed and pulled into a tunnel.