I played the game for about 40 hours the first week that it came out, beating the game and catching all the legendaries. I even defeated N. Then I've played it 20 hours since. I've completed most of the Unova game, but I play Pokemon white more. I've logged about 400 hours in that game, I mainly just trade and battle competitively in that game.
I thought that Black 2 was one of the harder Pokemon games. Ghetsis proved to be really hard, and getting through Victory Road took a log time as well. Also, it took m e hours to defeat N's Zekrom in Pokemon Black 2 because it was on such a high level. I had to find a hydreigon, train it, then I was finally able to defeat Zekrom with many hyper potions. It also too kme forever to catch Mespirit. :p