One of the best of the best!
Gameplay:
It's basically just like FF series. You run in a open field, fight some monsters along the way and get gold. There are also many bosses to fight with, which some you encounter more then once. Very nice.
Graphics:
... four words... Best Of The Best! I have not played any other game with such stunning visuals. It's like a mix between 2D and 3D. The attacks and spell casts will leave you speechless. Although, pity that the GBA has such of a poor screen resolution. If it was any better, then the game would look twice as good. Awesome Job Nintendo!
Sound:
This is also a very strong point of the quality. The sound effects sound just like a usual RPG game. However, I haven't seen as much as 99 midi's in a single game!
Value:
Very long game. Usually 30+ hours to complete. Worth the time!
Overall:
If you like awesome visuals and graphics (like me) and very solid RPG play, Golden Sun: The Lost Age is strongly recommended!