Judging from the first two hours or so, Rogue Legacy is a sprightly, fast-paced game that is easily playable in 5-10 minute chunks, and addictive enough that there is a real motivation to string those chunks together for extended periods of time. It's got a cartoony visual design that is simple, yet appealing. And it is punishingly difficult.
As near as I can see, whether, long-term, this game proves to be a cherished memory or grueling test of endurance depends a lot on exactly how the balance shakes out. The inheritance mechanic does, indeed mitigate some of the frustration that comes with playing a roguelike, but there's a fly in the ointment that threatens to sink the whole game for me. When you die, you keep your gold, but if you don't spend it before you respawn, and remainder is wasted.
What that means is that there are many runs where I die with absolutely no benefit. As the cost of upgrades and equipment rises, it takes ever more profitable runs to advance my character. In theory, it might be possible to get stuck, with a character not quite powerful enough to make progress to the next tier of power. I suppose that increasing player skill should make up for those situations, but that's a fickle and frustrating thing to rely on.
On the other hand, maybe I'm worry too much. I've only been playing two hours, and thus it's no surprise that I've not yet set the game on fire with my incomparable skill. Surely, by the time I get to hour 20, I'll be a veritable pro, and these early enemies will be like a joke to me. Or maybe not - I've yet to meet a boss that didn't tear me up in seconds.