Grim Dawn looks like Titan Quest and Diablo had a baby. They took the battle mechanics and skillsystem from Titan Quest. But they added a more fluent fighting speed to it, more gore, an overall darker atmosphere. Also there's a sh*tload more content than in Titan Quest, like:
-Crafting
-Roguelike Dungeons
-Factions (and with them, quest decisions)
-The Devotion System (which adds to the already existing 2-class-mix-skillsystem, so that you can really create a unique, yet powerful character)

I admit, the first act can feel a bit dragging, but as new possibilities open up for the player, it just gets more and more motivating to develop the character, and to move forward.

I'd say this is the best isometric ARPG which I've played, ever (honestly not a difficult thing to say as a die-hard Titan Quest fan ;) ). I've played this over a hundred hours while its Early Access versions, but I will keep playing it a lot more after its official release.

Addictive!