For those unfamiliar with the title, Gen IV is the 4th generation of Pokemon titles (Diamond, Pearl, Platinum), which were released here in 2007. These games brought radical changes to the gameplay, such as the physical/special split. Popularity for the series boomed with the coming of Wi-fi, and the Global Trade Center. In a few hours, the official release of Gen V (Black and White) will occur. This is also significant, as this is also a reboot of the series, where you won't encounter old creatures until finishing the main storyline, making the world seem fresh again. But I digress, as this is post is about the past, not the future.
Gen IV started it off with Diamond and Pearl, adding 107 new pokemon (with ability to import your Gen III pokemon), then continued with Platinum, fixing many things from the previous 2. Platinum also added many more attacks, and gave new forms to a couple pokemon. The Battle Frontier also makes a return (from Gen III's Emerald), adding a plethora of activities and unique battles within the game. The Frontier gave new challenges to even veteran players. This is all on top of the many features from previous generations (Day & night, breeding, swarms, Safari Zone, etc.).
Earlier this year was the US release of Heart Gold & Soul Silver. As the titles suggest, they are indeed the remakes of Gold & Silver (Much like Fire Red & Leaf Green of Gen III). Players were once again able to explore the lands of Kanto & Johto, as well as enjoy new features that weren't there back on the GBC. The Safari Zone that was absent from those games is available now, with several new twists. Placing objects within the different sections allowed new pokemon to appear, allowing you to customize your own unique safari zone. Pokemon from Gen III and IV that weren't available previously, are available now, even legendaries. The Pokeathlon replaces the contests seen in other Gen III & IV titles, in favor of a minigame collection involving the use of the stylus. One of the most exciting features introduced was the pokewalker. This was a special pedometer, you could load your pokemon onto, and walk with them, earning them experience as you walked. There were also minigames allowing you to earn often difficult to attain items, as well as capture pokemon. Some of these even had previously unseen movesets.
As we move to the future, we'll still look back to Gen IV. Once able to, we'll import our favorites (some even back from Gen III), conquering the toughest of challenges in this strange new land. With Fifth gen's release so close, the floodgates have already been opened, with a swarm of information already out there.
I'll be back later with more, I've got some nostaglia-ing to do.