Why it rocks:
The concept is very creative and fits very well with the Game Boy's portable nature.
Amazing graphics for its time.
Catching Pokémon and raising them as virtual pets is very fun.
The games are designed to be played with others; there are some version-exclusive Pokémon that can only be obtained by trading with other players who own the opposite version from yours.
The games don't punish you for only having one version either nor encourage you to buy both versions.
There are 15 different elemental typings that Pokémon can have, these types have a rock-paper-scissors nature where types have advantages and weaknesses against specific other types.
For example, Water is strong against Fire, Fire is strong against Grass, and Grass is strong against Water.
Some Pokémon have two types at once, which change the strengths and weaknesses further.
The game's world map is based on the real world Kanto region in Japan.
There are 151 different Pokémon to choose from for your team and you can use whichever ones you want. Different team compositions open lots of possibilities for strategies and combinations.
Using a Link Cable, you can play Pokémon battles with others.
The game's story mode takes you around eight Gyms where you fight "boss battles" followed by the Elite Four challenge and then the champion.
You have a rival that frequently challenges you throughout the game and it's enjoyable difficult.
Yellow is one of the few Game Boy games with voice acting, in this case Pikachu's voice.
Pokémon Yellow allows you to have all 3 Kanto starter Pokémon without glitches unlike its sequel.
Yellow updates a few species' movesets, such as Charizard learning Fly by HM, and Pikachu learning Thunderbolt.
Yellow introduces a few minigames starring Surfing Pikachu and Flying Pikachu.
The game has a fully unique and fleshed out battle system when compared to other RPGs at the time, as the attack moves are given different types that would be super effective or not effective if the Opponents Pokémon is weak or fully resisted by that attack move's typing, and it also uses different types of movesets that a Pokémon might utilize, or have stats that are different from each of them that range from the 300s or the 400s with 5 different base stats. Despite it not being as polished as later installments, it is very well executed and makes the game very fun & enjoyable.
All of the characters are very memorable and have a lot of likability to them, most notably Misty and Brock who have great personalities and have become some of the most iconic Gym Leaders in the series to date.
Many great designs for the Pokémon such as Charizard, Raichu, Nidoking, Dragonite, Sandslash, Marowak, etc.