The Gen 4 Pokemon games are regarded as some of the most ground-breaking entries in the series due to the number of changes they made to the series' mechanics. Along with these changes was the introduction of even more new creatures for players to collect, including many evolutions for monsters that previously had none. Although the Pokemon series isn't the hardest compared to other JRPGS, Pokemon Diamond and Pearl and Pokemon Platinum can be some of the toughest in the series, so players will want to ensure they have the best team possible for a successful playthrough.