The castle itself is the best part of the game, and the open world around it never quite catches up.
I went in expecting to bounce off this inside a week, because licensed games have a track record and I'd already been burned by two of them that year. Then I walked into the Great Hall for the first time, candles floating overhead, four house tables stretching out under a false night sky, and I spent my first two evenings ignoring the main quest completely. I followed staircases to see where they went, found a hidden room behind a portrait because a ghost had looked at it funny, stood around watching paintings argue with each other. Avalanche Software understood that the castle was the pitch and it's the one part of the game they refused to pad, which is why the castle rewards aimlessness while everything outside it rewards checklists.
Sebastian Sallow's storyline is the other thing here I'd call great. It's a thirteen-quest thread about a Slytherin classmate trying to cure his cursed sister, and it walks a good deal further into the dark than I expected from a game this family-friendly, up to and including offering to teach you the Unforgivable Curses. I said yes to learning Crucio because a fifteen-year-old asked nicely, then used it through the entire back half of the game, and no professor, no prefect and no plot consequence ever said a word to me about it. I kept waiting for the bill to arrive, right through the credits, and either that's the funniest oversight in the game or it's the bleakest available fact about wizard society, and I've decided not to investigate which.
“The castle itself is the best character in the game.”
Outside the castle gates there are 95 Merlin trials, which is the same handful of puzzles copy-pasted across an entire map. I did about sixty of them before admitting to myself that nobody was making me, and the bandit camps and collectible clutter fold up the same way somewhere around hour twenty, so what's out there is a checklist wearing a wizard hat.
Combat turned out better than a licensed game needed it to be, and by midgame I was chaining Confringo into Levioso into a well-timed counter, flinging enemies into each other's attacks, which held up for the whole run. The Room of Requirement nearly rescues the middle hours on its own, a customizable space for growing plants, brewing potions and housing the beasts you rescue, and I lost more time arranging furniture in there than I spent on the last three main quests put together. House choice changes your common room, a couple of side characters and close to nothing else, and I picked Hufflepuff for the kitchen-adjacent common room and stand by that.
I played on PS5, where performance holds steady outside a few crowded courtyards, and the PS4 and Xbox One versions that came later reportedly struggle badly, so play it on current hardware if you get the choice. I never worked out whether the Merlin trials were meant to be done in that volume or whether somebody just needed a number on a feature list, and nothing in the game or the interviews I read afterwards clears it up. My map was still crusted with icons I'll never clear when the credits rolled, and the save file has been sitting there for two years on the theory that I'll definately go back and finish them off.