I'm playing through all the games in order and am currently on Emerald. Surprisingly the leveling up on this game has been the most frustrating so far. I really like Emerald, but I think Crystal *might* be my favorite currently? I kind of like the challenge in that game, the leveling frustrated me at first, but once I reached the elite 4 it was actually less of a hassle to prepare than it was with Red. I do love the little custom input things in Emerald thought.