I think there's a common sentiment shared between each player on this thread myself included. Lemme' sum up:

The gameplay is great. Animations feel smooth and killing=satisfying.
There is simply not enough content or depth throughout every aspect of this game. Skill tree (notice singular) is meh, passive skills are far from groundbreaking, and personal customization is almost non-existent.
The game has such great potential though it is overshadowed by the troubling feeling that it has not been engineered to improve enough to generate a lasting interest.