In Pokémon Black 2 and White 2, there are areas known as the Black City and White Forest respectively. In both of these locations is a tower of sorts, with a lot of Pokémon trainers and mazes. At the top of each one, there is a difficult boss fight, where the player has to face Pokémon such as Volcarona and Cresselia. Did you ever clear the White Treehollow/Black Tower? If not, how far did you get? How high of a level were your Pokémon? How many levels did you gain? Did you have a lot of game overs? I made it through the White Treehollow once, and it took a long time, considering all of the different trainers in the tower. I beat the final boss with my whole team still alive, and by that time they were all in the higher level 80's from all of the training I received in the tower. It was quite the trial to make it through the whole thing, but I somehow did it.