Pokémon Crystal Version/Legacy

While Gold and Silver introduced the majority of Generation II's contributions to the game mechanics, Crystal also featured several additions to the franchise that continue into the future. First, Crystal introduced the option to play as a female character. The game also featured the first Move Tutor of the series, as well as the first. This was the first game to include animated sprites for Pokémon, though this only applied to front sprites (back sprites remained still as they did in previous games). This feature was absent in later games until it was reintroduced in, after which it became standard. Back sprites did not become fully animated until, which also added animations for important Trainers such as Gym Leaders. In, sprites remain animated throughout the battle; before these games, Pokémon Crystal was the only game that had more than two frames per animation.

Even though were the first games to use Legendary Pokémon (specifically  and ) as game mascots, it was Crystal that incorporated them into the plot for the first time. The story additions involving the Legendary beasts (most prominently ), Ho-Oh and were unprecedented, since up until then no Pokémon had been referenced in the dialogue on more than one occasion. This was also evident in the fact that the Legendary beasts received a unique battle theme, and in that the plot climax was no longer limited to thwarting Team Rocket, instead culminating in the battle against Suicune at Tin Tower. Later generations focus on their game mascots as part of the plot involving the villainous team of the respective region (with the only exception being the remade versions; follow 's footsteps, and  are similar to Crystal in keeping the two stories separated).

The Japanese version of Crystal notably introduced the ability to link to a wireless connection and interact with other characters (via cell phone). The Game Boy Advance Wireless Adapter also enabled this ability in Generation III (albeit to a far lesser extent, due to the Wireless Adapter's limited range), and the Wi-Fi capabilities of the Nintendo DS completely optimized the concept in Generation IV games. The GS Ball event was the first time where an event Pokémon (in this case ) could be caught in-game as opposed to being directly downloaded to the cartridge; this went on to be the case for several such Pokémon in subsequent generations.