I never did beat the third boss. It was a fast-moving, flaming skull that trailed behind it fireballs, which would linger for a significant amount of time, making the area a dangerous obstacle course to try and dodge through. I think I probably could have handled that, but there were also spiky metal balls bouncing around, and it was just too much. I wound up going through the easier levels in search of enough gold to level up until I was stronger than the enemy.
I never quite got it. I was only skilled enough with a few of the classes. If I weren't playing a Barbarian, a Paladin, or a Hokane, I'd consistently die before gathering enough gold for an upgrade. In the end, I died about 300 times without beating the game.
So what's the verdict? I enjoyed grinding for gold with an amenable class. I hated fighting the bosses. I'd rather not have bothered playing the classes in which I lacked skill. I don't think I can simply average my reactions. I guess I liked it, overall, seeing as how the gold grinding took up the largest amount of time. Although the reason it took such a large percentage of my time is because all the other activities killed me very quickly.
If I'm being honest, though, I'd have to admit that I never really bought into the central ethos behind Rogue Legacy. It's a game that pushes you to your limits, and beyond, where if you succeed at a challenge, that is a cue for the game to throw you a harder one. And it is that constant process of self-overcoming that is the reward for playing the game. As Nietzsche said, happiness is the sensation that power is growing. And for those who are willing to endure it, Rogue Legacy offers pure, distilled happiness. Unfortunately, I am somewhat less than a gaming ubermensch.