A recurring oddity in the Pokémon games is that the Gym Leader and later Elite Four member Koga, the Kanto Region's Poison-type expert, threatens to defeat his opponents with both Poison and Sleep tactics. In Red and Blue, he states:


In Gold, Silver, Crystal, and their remakes HeartGold and SoulSilver, he states:


In FireRed and LeafGreen, he states:


Despite this, the only game in the series where Koga's main team uses any Sleep-inducing moves is Yellow, where two of his Venonats have Sleep Powder. In contrast, all of Koga's teams have incorporated Poisoning moves, with some of his teams being entirely composed of Pokémon using such moves. Although possibly a mistake, this might also tie into the theme of misdirection, which would be fitting for the ninja-themed Fuchsia Gym.

In the original Game Boy release of Pokémon Red and Blue, examining the television in the living room of the player's home in Pallet Town from the side would show the message: "Oops, wrong side..." In the Generation III remakes, Pokémon FireRed and LeafGreen, the aforementioned TV has been positioned against the wall in such a manner that it cannot be approached except from the front, facing the TV screen. However, by using a cheat device to enable a player to walk through walls, then approaching the TV from the side through this method, it will show the same message, despite being impossible under normal conditions.