Don't believe the GameSpot review.
I had a lot of fun playing this game, even though it did start to get tedious after the main part of the storyline. Getting to play as a Pokemon is fun, and you can even evolve yourself. I started as an Eevee and ended as a Vaporeon. It's a straightforward dungeon crawler, but it's still lots of fun. Being able to progress the storyline kept it interesting, once that was over it started to get a bit droll.
The graphics are fine, nothing spectacular, and the storyline is straightforward. There's nothing else I can really say about those. Same with the music. True, the game itself is nothing that special, but it's still worth a higher rating than GameSpot gives it. Give it a play and decide for yourself, but if you are a fan of the Pokemon series, you'll probably enjoy it.