Described in terms of mechanics Rogue Legacy is an exploration platformer that contains traces of roguelikes (permadeath, randomly generated dungeons, hard as nails) and 2d action-adventures/action-rpgs (item and skills updates, a sort-of persistent free-roaming castle to explore). But to be honest, the most apt description is crack in digital form.
There has been a lot of discussion in recent years about games that feed the psychological reward mechanisms just the right way to keep you playing even if you don‘t want to. And Rogue Legacy is a prime example of that kind of design.
Rogue Legacy can get a bit grindy at times, but most of the times it‘s a perfectly paced mix of exploring, leveling your character template and advancing by collecting money and occasionally killing the various bosses in the castle. Each time you feel frustration raising its head, you soon get a new skill or a new update to make you feel like you‘ve came a bit further, despite dieing the Xth time.
And like in most roguelikes, you‘ll die a lot. But unlike in roguelikes or any other games, death is not a failure mode to teach you how to become better at playing the game, but it’s a necessity to advance. After each death you can chose one of three successors, spent the money you’ve earned on your previous run and go at it again.
It‘s fun, but not all the time. But the game keeps you going. And going.