For the true hardcore GTA fan
I personally really enjoyed this game. It gave me exactly what I was expecting out of a GBA GTA game.
Their are a few problems with the game that really sit on the fact that this game pushes the limits of the GBA. Game stutters when a lot is happening. Targeting might be difficult for new GTA fans. Lack of buttons causes some control issues.
But overall, this is a GTA experience on the go. The game recreates Liberty City seen in GTA III taking place between games. It has a standard GTA style story.
It doesn't age well. If you have a PSP, play the superior Liberty City Stories and Vice City Stories. If you own a DS, you might want to give this a whirl, but as soon as China Town Wars comes out on the DS, their might not be a point.