I will have to disagree with this and say, the only one that feels remotely too difficult would be Cutthroat, but mainly because the bosses have waay too much health. The rest of the Dungeon with Cutthroat, and with the rest of the feats, are fairly simple or easy. Feats are also better when you're in a three stack, and not when you're soloing. I wouldn't recommend running feats solo, unless you are prepared for a challenge, and it will be 100% difficult.