I'm a big Lovecraft fan - but I'll +1 w/Stoic and tomos. These are games we're talking about. They don't really need to toe the line on Lovecraftian themes or nihilism to be good games.
However, if you're truly a Lovecraft fan, the only
possible game involving Cthulhu would be preventing his minions
or some misguided researchers
from setting in motion a chain of events that will bring on the advent of what the Necronomicon calls the Strange Aeons
where the Old Ones shall return to once again dominate and rule our dimension - "and even death may die."*
In short, you can't fight Cthulhu. Cthulhu is the failure
state. If Cthulhu appears, the game is over.
The best possible win would be to simply survive - ideally with your sanity intact - till the game clock runs out. With Cthulhu, there is NO
possible win - there's only stalling off your own inevitable
failure. Your goal isn't to win the game. It's to not
lose it. And that would not
be the most satisfying outcome for the average gamer.
FWIW I've played some very good Lovecraft-themed games with heavy duty HP fans over the years. While these games were often extremely intense and very enjoyable to play, the "don't lose" end goal tended to leave all of us with a certain sense of frustration and futility by the end of the game. With Lovecraft, there's no real "feel good" ending possible. So unless you're a diehard fan like we are, that probably wouldn't have been considered a 'fun' evening for most people. Not that that's a bad thing for Lovecraft fans. That act of putting up a bold but ultimately pointless front in the face of utter hopelessness and cosmic dread is what makes Lovecraft so entertaining. At least for those of us mutants who have been bitten by the Cthulhu bug.
*Note: losing to Cthulhu is a particularly nasty fate since Cthulhu is (among other things) an "eater of souls." Your very being becomes trapped like a fly in amber. Those "killed" by Cthulhu don't "die" in the usual sense. Your consciousness gets absorbed into the mind/person of Cthulhu, where it will get to explore the ceaseless and infinite number of ways you can suffer death and pain in Cthulhu's psychotic imagination.
Like Leviathan's Labyrinth in Clive Barker's Hellraiser
stories (which Barker has said were heavily influenced by some of Lovecraft's themes and ideas) Cthulhu is the living embodiment of what we would consider to be hell
in the most classic and literal sense. "Enter Ye into the place prepared for you from everlasting unto everlasting. Now Ye shall truly never
Such is the fate of those consumed by the eater of souls.
Wow! Bummer huh? Talk about something that could ruin your whole day...