The game is a good game because there is some difficulty and you need to keep on leveling up your pokemon.
However, the game can become too easy if you use overpowered Pokemon. For example: Charizard and Blastoise are strong, being able to use Flamethrower or teaching Blastoise Ice Beam and Surf make the game relatively easy.
Also, catching Snorlax and then using him makes the game easy as well because Snorlax has great HP stats and attack power.
Also, catching Zapdos at the Power Plant then makes the game very easy as you can teach Zapdos ThunderBolt and Fly, which makes it Overpowered.
Also, if you decide to get a Gyrados early on then the game becomes easy due to Gyrados having such a high attack stat.
The game truly has a challenge to it when you choose to use Pokemon that are less strong, pokemon who are not really “game winners” like a Blastoise-Zapdos combination.
-DJ ROBO BISCUIT