For some reason, I was constantly reminded of Resident Evil (which I was too wimpy to play, btw... I just watched my brother play) when I was playing the game. It's a "first person shooter" kinda game, where you're Harry and you run around... doing stuff. Your "gun" is your wand, and throughout the game you learn four spells total. Your standard spell is a Knockback Jinx, which can do just about anything to stuff you can fire at (little sparklies appear above stuff you can "shoot"). Anything requiring a different spell has a different-colored sparkly above it, and you just aim and cast that spell automatically - nothing hard.
The animation is okay - but I absolutely HATE Hagrid's look. He's this chunk with a pointy head, and his face is flat and on a slant. Everything else is tolerable. You pretty much follow the storyline, and are only allowed to go into certain areas at certain times, after fulfilling various tasks and quests.
An annoying feature is you're sucked into doing something before you know it, so you wanna save often. A less annoying feature is you never really die - you go to Madam Pomfrey; and you have limitless "lives".
Several tasks require at least 2-3 times to run through before you get the hang of it (it did for me, anyway).
Overall, it's a pretty good game, but one I've gotten sick of after playing through it twice. As mentioned above, getting all the wizard cards is difficult. Of course, me being anal-retentive and perfectionist and stuff, I'll prolly keep playing until I find all the damn cards.