Yes, it had it flaws: it would have been nice for the bard to cast spells, and for the druid to cast spells.
But so much of it was letter-perfect "this is part of a D&D campaign". And the little touches were wonderful.
Seeing places I have had characters in (most of the D&D games I was in for long campaigns were in the Realms). Neverwinter, Icewind Dale, all of that. Seeing a druid wildshape, along with that sequence. The bickering between friends and dropping it because there's danger, only to pick it up immediately after.
The monsters - perfect onscreen versions of the mimic and the gelatinous cube and the displacer beast.
Some druids really just prefer wild shape over spells, too. So it's not entirely out of the realms of possibility.
And I loved the intellect devourers.
And the bit of pique at not being attacked.
And then the things that made you see the game mechanics if you know them well enough. The "my visiting friend from out of town wants to play tonight, let me give him a character to let them play" that is Xenk. The "what do I do now" when Simon destroys the bridge and the hither-thither staff is suddenly found.
So much of the "no plan survives contact with the player characters".
And the creativity used with stuff in ways a DM would never think of, like using the hither-thither staff on the frame and using it to get it into the treasure room. That was the kind of inspired madness you get in a game when things go well.
And when it ended, I wept.
For my late good friend Mike, who DM'd D&D and who I DM'd for, who would not get the chance to see it, and who I think would have loved it, even as he bitched about things like "but druids can't wildshape into owlbears!" and "he didn't use any of his paladin abilities!".
And then I would have looked at him and said, "But we got to see Szass Tam! And Neverwinter! And..."
And there would have been hours to talking about it.
The bittersweet thoughts of lost friends that go alongside the movie.
To me the single most D&D moment in the entire movie was whenever they got a new item, Edgin just handed it to Simon and went "Hold this."
Simon was clearly the one managing the party inventory.
And my friends and I all agree that Xenk is the DM insert character, who the DM introduced to get the party back onto the main story path.
Now, imagine this: People who see the movie because Fun Movie... then start playing D&D and seeing it again!