Darkest Dungeon is a great game!
The artwork, theme and game mechanics on their own almost make it worth the buy.
I like the game a lot. The design is amazing! The comic graphics style and the lovecraftian theme are both high quality and it's amazing how well they work together. They give the game a special feel that I like. It just fits!
The game mechanics, e.g. the combat system, are ingeniously simple and work well.
Yes, the game is difficult, especially Level 5 upwards!
After you found out what's important in the game, Level 1 and 3 is not that hard and very enjoyable.
On the verge to Level 5 dungeons the difficulty level rises too steep for my taste. But after several approaches and managing to buy the appropriate armor and weapons level for my heroes, it became almost manageable for me. Level 5 Bosses, the Darkest Dungeon and the Siege Town Event are still very problematic, but I guess it has to be that way. The game is meant to be difficult!
It's an outstanding game!