Each class has a gimmick-or "specialization"-that unlocks as you progress through the game. The Barbarian, for instance, can lug around a huge arsenal of weapons and gains "expertise" with each as you use them, granting buffs and special effects. The Necromancer can choose between different types of minions or sacrifice them to extract their power. The Rogue has three specialization options, one of which is a WoW-like combo-points system. Every class has its own personality and quirks, and they're all a blast to play.
There is a story, told mostly through notes left strewn around the environments, but I’d be lying if I said I paid any attention to it. The draw here is the gameplay loop, and if what I’ve described above sounds tedious to you, the game is absolutely not for you. Rogue Legacy 2 is a game about repeated failure, and only slow, incremental progress will lead to your success.
"Deckbuilding roguelike?" Whatever you want to call it, this game is fun.
If you're a fan of the series and are willing to go through the whole "expansion that fixes the game" thing again, buy it—now.