Console: Gameboy Advance
Many fans initially complained about Ruby and Sapphire’s incompatibility with Pokemon Gold/Silver, and for good reason–to date, they’re the only sequels in the main Pokemon series that don’t allow you to import your beloved Pokemon from the previous generation. However, this break in lineage allowed Game Freak to make massive additions and improvements to the game mechanics, and over time it proved to be a trade-off that was well worth it.
Ruby and Sapphire introduced more new features than any Pokemon game since, all of which are still integral to the series, including abilities, natures, double battles, and the refinement of the IV and EV system. While not being able to transfer your shiny Gyarados was a huge bummer at the time, we have Ruby and Sapphire to thank for the richness and depth we continue to enjoy in the series today.