Yes this game "HeartGold/SoulSilver" is definatly one of the best if not thee best handheld pokemon or games to be made so far. This is basically a remake/revamped Nintendo DS version of "Gold/Silver" Game Boy Color versions and the difference between the old version and revamped Nintendo DS versions are quite collosal.
"HeartGold" - Revamped 3-D enviroment/surroundings and you have an interactive dual screen for mini games you can play using Pokemon you capture as you go on through the game, also interactive options/menu (i.e save, Pokedex and Pokemon also Pokegear.) As well as that you can use the pokewalker get catch pokemon on the move and make also help level up pokemon you have already captured (if transmitted to the pokewalker.) Also you have a pokemon (whos first in your six pokeman squad) walking around with, pretty cool if you ask me.
"Gold" Game Boy Color Version - Its very Retro but not as good as HeartGold is with its 3-D modern graphics.
However if one thing has stayed the same through every Pokemon hand held RPG game up to this one its definatly, the gameplay, its the same battle system and how you catch pokemon. Which is good as the gameplay is basic,simple and enjoyable old and or new pokefan. I recommend you to buy this game its got hours of gameplay to explore two massive regions and fill up that near massive 500 pokemons worth Pokedex,Gotta catch em all!, right?