While ARPGs typically stick to a tried and true combat formula, some entries buck those trends and try something different. Book Of Demons goes that route, starting with a typical Diablo story before taking a number of major twists and turns.
Book of Demons deftly incorporates deck-building elements and interestingly puts procedurally-generated dungeons on rails. It gets extra points for graphics done in the style of paper tabletop minis.
If you've played every other hack 'n slasher out there, be sure to give this refreshing entry a try.