Interesting--I didn't figure it out it was Cthulhu until the wings unfurled. I know the wings had been mentioned before a couple times, but for some reason I hadn't connected octopus head with wings until its reveal near the end. I do tend to agree that Cthulhu as a spirit form doesn't make a ton of sense in that, sure, maybe you can summon it, but maybe instead of killing a handful of your enemies it will kill everyone on your continent including you. For that reason I like the story better without the Cthulhu connection--I think it stands well enough on its own without that connection (even though that connection was no doubt necessary for it to be published in the antho it was published in).
I liked the characters, interesting magic system, good action.