Somewhat disappointing given the source, but playable and slightly enjoyable.
To begin with, the plot was seriously ridden with disappointing no-nos. The later games had that level of realism and game-play which was quite convincing, but here, Potter and his friends seemed to go into different places at inconsistent times, with terrible receptions. For instance, Professor McGonagall off-handedly speaking with Harry after he engages in a high-chase, action-packed broomstick match with Malfoy over Neville's Remembrall wasn't only just unconvincing: it was almost comical. Like that episode, there were some others that never seemed to follow the original content of the novel and film.
In fairness though, it did have some spells that will be quite interesting to first-timers (though pale in comparison to the incantations that would follow in its successors), and though the game-play was quite fast (impossibly so, if I may add), it managed to SOMEHOW remain rigged with the original content. I would consider my reaction to be a bit mixed. Oh, and one more thing - Voldemort's appearance towards the end wasn't just unconvincing: as a figurehead of pure evil, he was extremely laughable. That's just one of the many flaws this game could have been infinitely better without.