I'm pretty sure that Pokemon is one of the most hardcore RPGs out there right now. To put it simply, I actually stopped playing the game by the fourth generation because the game got _too_ complex - for context, I have several Pokedex guides on my bookshelf, used to work out Hidden Power calculations by calculator and paper, have a friend I used to plan teams with, and even know about the Mew glitch in Red/Blue.
I was okay with the hidden effort value training in Generation I, and the hold items, breeding, special attack/defense split and new types added some welcome complexity in Generation II (not to mention the much-needed nerf to Psychic types), but the effort value cap, the personality values and abilities started to overwhelm me by Generation III. Once the physical/special split happened in Generation IV, the complexity of the game was completely lost on me, and I decided I had to quit. I haven't read what Generation V brings, but I cringe just thinking of the strategic depth needed to master the game by the Black/White installments.
Super World Cup Fighter II: Championship 2010 Edition








