Harry Potter definitely hits the spot graphically. Each of the characters is very well animated, especially in the spell learning sequences. While it was great to see, it does end up getting in the way early in the game. For example, while casting the 'Flipendo' spell (which is your main offensive spell), the casting animation takes so long that it is not uncommon for the enemy you are casting at to get in a quick, cheap shot. I also found the environments to be lacking as well - mostly in variety. There is no denying they look great, but after awhile all of the dungeons begin to look the same.
Using sound tools from Factor 5, the developers were able to squeeze the most out of the GBA sound hardware. While I would have enjoyed hearing some music tracks from the movie, what's here is very enjoyable and always blends in with the action on the screen. The voice samples are good, so good in fact that I found myself switching spells just so I could hear the spell names.