Sadly I've to agree with most of what
Pope Amole II wrote.
The game does have a great atmosphere, and it's certainly fun for around 20 hours, but in terms of gameplay there's currently too little to keep it fresh for much longer.
Progression is currently mostly grinding, with the only thing you get from it being higher numbers and a few new enemies.
The cove update has added some fresh ideas insofar as enemies now interact more and have a few nasty synergies, offering the potential for more tactical combat. I hope they expand those abilities in scope and add them to the old monsters from other areas as well.
Still, the actual gameplay is indeed somewhat shallow. Dungeon crawling is as simple as it gets, as typical dungeons are just a sequence of rooms connected by (straight) hallways, without any surprises or interesting layouts and only the simplest non-combat challenges (traps with disarming chance, thematically consistent stuff to interact with).
Quests ultimately always boil down to the same thing: Make your way through a dungeon, do some fights until you have reached the goal, return (or get killed along the way).
Even the stress mechanics, which were one of the main selling points are not particular deep - they serve as a 2nd health bar with some nice quirks and have their own way to regenerate, but I feel as if they usually simply not matter enough during normal gameplay, nor is the build-up (or removal) solved in a very interesting way.
So far it's not clear to me how they want to tie the game together for the endgame-content (the "Darkest Dungeon"-dungeon). If it will be nothing else but leveling up some heroes to kill all the bosses (of which there are quite a few as every boss has 1 incarnation in each of the 3 dungeon difficulties) until you can have a go at the final dungeon/boss after what would probably be 40+ hours, I seriously doubt most people will ever play through, since it would overstay its welcome for most well before reaching the ending. Just as the last sentence of mine has.
Rather it might be a nice game for a couple of 5-15 hour runs given some randomness to the encountered monsters and bosses, or maybe good for playing it once at 25 hours. Everything above that would be pushing it, as it stands now.
So, ultimately I got my money's worth of fun out of EA already and I will keep playing it from time to time when in the mood, but it didn't quite turn out to be what I had hoped for.
Ironically my very first impression during the kickstarter was rather accurate - I thought it's a nice looking and atmospheric game with somewhat samey and boring gameplay.
EA is not over yet, of course, so there's yet hope they will add some things that would fix its shortcomings, but their work in the last months has somewhat dampened my hope that they will do so - I think their vision is pretty close to what the game currently offers.