One of the most common questions Pokemon players constantly wonder about when it comes to any Mainstream Pokemon Game is what Starter Pokemon they should select when beginning their new journey. Though any Mainstream Pokemon Game can be won no matter what Starter Pokemon is chosen, this remains a popular question. Usually, most players pick whatever Starter Pokemon they personally like best, especially since it truly doesn't matter which you pick. However, some players are a little more strategic than this, wondering which Starter Pokemon will have more success against Gym Leaders and what Starter Pokemon will make the game a little more difficult and competitive.
As a whole, selecting Bulbasaur will make things much easier for yourself. The main reason for this is because Bulbasaur will have a key advantage against the first two Pokemon Gyms, since Grass Types are super effective against Rock Types and Water Types. On top of this early upper hand, Bulbasaur will also fair well against the third Pokemon Gym (since Electric Type Moves aren't very effective against Grass Types), the four Pokemon Gym (since it will be on an even playing field against other Grass Types), and the final Pokemon Gym (since Ground Types are weak against Grass Types).
But if you're looking for more competitive run through the Kanto Region, it might be best to go with Charmander as your Starter Pokemon. Unlike Bulbasaur (and even Squirtle), Charmander will only have the upper hand in terms of typing when you face the Grass Type Pokemon Gym in Celadon City. Outside of this Gym Battle, Charmander will always be on either a neutral playing field or at a disadvantage. Charmander will also struggle early against the first two Pokemon Gym (Rock Type & Water Type).