Now, before we go on, I know what you're wondering: what did he think of Yellow version? Well...it was okay? I suppose? I'll admit, I was excited to play an adventure more like Ash's at first, but as its gotten older, I have to admit, it's grown kind of stale.
But back to Gold and Silver. One of the first things that kids knew about it was that there was going to be a TON of new pokemon, around 100. They were still based on childhood experiences of the creators like Japanese mythology and manga, much like bug collecting in the first one.
There were a bunch of new elements added in as well. Firstly, the dark and steel types were added, dark mainly to balance out the somewhat overpowered psychic types (alakazam). There was breeding (which we'll get in to more in a minute) and a larger variety of pokeballs, including custom made ones depending on what apricots you've collected. One aspect left over from yellow was the idea of the relationship you had with your pokemon. If your pokemon got hurt or lost battles a lot, he'd like you less and less, but if you gave him items, took care of him and were successful, he or she would like you more and more.
