It's an open-ended RPG like Oblivion, with a huge sprawling world... but with terribly unbalanced combat that enables simple woodland creatures to easily kill you by means of a "stun lock" while the big bad guys in the game (Orcs) are ridiculously easy to beat. The game also has terrible performance compared to Oblivion, but those issues are solved by a community patch - so d/l this if you're planning to play.
For a "new" single-player RPG, I'd recommend Drakensang: the Dark Eye. This game combines the party-based combat of NWN 2 with a unique, highly detailed fantasy setting (Aventuria) comparable to Tamriel of Elder Scrolls (but even more detailed, judging from the many lore books that have been released).