Hard to describe is an apt description; this game really stands on its own and fortunately that's for the better.
Call of Cthulhu is a very novel game. While most gamers would dismiss it as another Doom clone with a name that outstays its welcome at "Dark", CoC:DCotE is both innovative and surprisingly sleek. The absence of any kind of HUD was one of the first things I noticed about the gameplay, one that shocked me at first. No health meter, no bullet counter, no blue lady dancing around my screen telling me I had better kick Regret in his covenant balls or else have the earth royally boned. No gentlemen; just my hands, my feet, and a dark little village in the middle of God knows where filled to the brim with angry fish people that want to make my intestines into a nice souflee.
The second thing I noticed about this game that seemed off were the recurring visions of monsters running around piddling about that apparently wren't really there, at that point I assumed either A) my disc has more holes than a woman's rights activist in Iran, or B) my character is whack. Fortunately for me it proved to be the latter, as this game was one of the first to introduce a "sanity" element, which although not perfect only added to the overall experience. Your screen will sway, your character will whisper chants to himself (Cthulhu R'lyeh wgah'nagl fhtagn!) and if you go bonkers enough you'll end your little world of misery with a .45 to the head. Youch.
Now as far as story goes this game is on par with... well I suppose Bioshock might be an apt comparison for all you young people. It's dark and gloomy with great voice acting and dialogue, enough plot twists to satisfy even the most cynical of critics, and an ending that feels like Conan O'Brien just flew through your window and kicked you in the balls. Yeah, it's trippy.
I suppose my only quible with this game is the difficulty of some of the puzzles every now and again. Now for all you cheating little bastards there are tutorials on youtube you could pull up promptly, but in my opinion the satisfaction of finally solving the stupid things is much more gratifying, and in retrospect hard puzzles are much more welcome than the industry standard "put round block in round hole" that most shooter fans are used to.
To summarize, I know right, I would recommend this to anyone looking for a story driven game with some interesting ideas and a whole lot of juju, that is if you can ignore the fact it's almost an antique.