Despite being the best-selling games in the franchise in the past 20 years, Pokémon Sword & Shield left a number of longtime fans disappointed. While there were a number of reasons for the disappointment, such as a cut Pokédex number and sub-par graphics, one of the loudest criticisms was that the games were just too easy. This was a particularly disappointing issue for many, considering that the core Pokémon games used to provide a legitimate challenge.

Pokémon games are built on their battles, and Sword & Shield are sorely lacking in this regard. The games' addition of EXP candies and the extra-generous EXP share mean that the player's party will almost always be overleveled. Combine this with the fact that many gym leaders have small and underwhelming teams to begin with, and players are left with only a plethora of easy and forgettable battles to sleepwalk through.

Related: How To Play "Hard Mode" In Pokemon Sword & Shield 

The importance of difficulty in a Pokémon game is vastly underrated. Being faced with a challenging opponent that requires strategy and trial and error gives the player the ability to form a connection with their virtual team. Barely getting past a tough opponent because the player's starter Pokémon was able to pull out a critical hit at just the right moment makes a player love that Pokémon even more. These tense moments are what make up a memorable Pokémon adventure, and is what Sword & Shield were mostly lacking. Here are a few of the best Pokémon battles from the series' history.

Pokémon Gold & Silver - Battle With Red

Red in Pokemon Gold and Silver

Climbing to the top of Mt. Silver at the very end of Pokémon: Gold & Silver and being met with the main character from the first game was a twist nobody saw coming back in 1999. Red, as he was called in-game, had a loaded team. All three Kanto starters were included at level 77, and offensive powerhouses Snorlax and Espeon meant the player was in for a rough time if they weren't prepared. Red's signature Pikachu was easily the weak spot of the team, but still a nice piece of fan service.

Pokémon Omega Ruby & Alpha Sapphire - Battle With Wally

Wally pokemon characters missed in anime

In Pokémon: Omega Ruby & Alpha Sapphire, Wally acts as a second rival that the player faces numerous times, but he's typically not much of a challenge until the final encounter at the Battle Maison. This time Wally is prepared, as he comes in with the majority of his team at level 79. His team has excellent type coverage, with heavy hitters of the water, fire, and grass variety in Azumarill, Talonflame, and Roserade respectively. The Ralts that the player helped him catch early on in the adventure has also become a wrecking ball of a Pokémon as a level 81 Gallade. This battle is tough enough the first time, but the games took it a step further by having Wally's team get even stronger with additional battles.

Pokémon Diamond & Pearl - Battle With Cynthia

Cynthia Pokemon

Cynthia, the champion of the Sinnoh region, is widely considered to be the toughest champion in the entire Pokémon series. Her team is incredibly diverse, featuring excellent type coverage and very few shared weaknesses. At the time, she had one of the few Pokémon in the series without a weakness in Spiritomb, and possessed two of the hardest-hitting and rarest Pokémon in the Sinnoh region in Garchomp and Lucario.

Related: Why Registeel Was Censored In Pokémon Diamond & Pearl

Cynthia was such a challenge in Pokemon: Diamond & Pearl that they actually had to knock a few levels off her entire team in the Platinum version.

Pokémon Ultra Sun & Ultra Moon - Battle With Ultra Necrozma

The Ultra Necrozma encounter in Ultra Sun & Moon is the toughest single Pokémon battle in the series. Not only is this terrifying creature level 60 when encountered, but it also has many of its stats boosted by its aura. This is a notorious difficulty spike in the game, and while some might think of that as a negative, many praise the fight for forcing them to think strategically, rather than just hammering their strongest moves as one can do with most wild Pokémon encounters. This is certainly a battle where Pokémon players need to have plenty of Revives and Hyper Potions on hand.

Next: What Ultra Shiny Pokemon Are (& Where To Find Them)