It’s cheap. If I was making an indie movie, my first instinct would be to set it in one or two locations.
Legend
Dragonslayer
The Dark Crystal
Labyrinth
I’ve never played Dungeons and Dragons, but I believe that–despite the name–they don’t have to spend all (or even any) of their time in a dungeon.
(Having said that, we really need a movie that combines a dungeon adventure with a cooking show.)
I think all the Conan clones in the 1980s killed the low-budget high-fantasy market. Nobody wants another Deathstalker.
Is that not literally the plot of Lord of the Rings: Fellowship of the Ring?
Yes, I was going to say that LotR, especially the part through the Mines of Moria, is quite D&D-esque. There’s a perception/lore check to get into a large enclosed space, the group wonders which way it should go, they find an ancient tomb with plot-relevant knowledge, a failed dexterity alerts orcs, superspecialmagical armor saves the hero against a critical hit and the fight ends with the defeat of the cave troll boss.
It would be difficult for the LotR movies not to be reminiscent of D&D because D&D is largely based on the LotR books.
Because it would be boring? Or possibly the other way round; if it was any good it wouldn’t be possible to tell that it was based on a D&D adventure.
The Sindad movies or Clash of the Titans ( 1980s ) had some of this. You could also watch the excellent Lord of the Rings movies.
In the 1990’s there was a game called Death Trap Dungeon. It could make for an awesome movie.
But its SyFy Channel “sequel”, Dungeons & Dragons: Wrath of the Dragon God, is actually pretty entertaining if you are/were into playing D&D. Although low-budget, it does a better job at staying true to the game and almost feels like you are watching a movie version of a D&D session.
The 13th Warrior had a dungeon - well, cave - crawl section.
Thanks for the head’s up! I’ll keep an eye open for it.
What if you had a movie where a half hour was Ebonysilver the Paladin and Ghandallf the Wizard debating whether or not a Minor Illusion of a mirror casts a reflection?
Followed by them refusing to speak with each other due to a heated disagreement on grappling rules!
…As an aside, have we ever had that debate here? Because I’ve wondered about it many a time. Because the rules try to be clear about what certain kinds of illusions can and cannot do… but a mirror seems to be in the “can” category, and if that’s allowed, then you can use it to make illusions of things in the “cannot” category.
An illusiory image doen’t cast a reflection - it creates an illusion of a reflection.
The now banned OP didn’t ask the right question but I’m pretty sure I know exactly what he/she meant. A properly made D&D movie with Drizzt Do’ Urden would be awesome.
Wow! I came here specifically to mention Lodoss War. Glad you beat me to it!
Rejoice, that manga is now available in English under the title Delicious in Dungeon (print or ebook), and it is very entertainingly weird. It plays the “cooking dungeon monsters” premise extremely seriously (have you ever wondered how to prepare a living armor? Wonder no more!).
And it should totally get an anime. 
There are plenty of streamed or podcast RPG sessions with decent followings, but I think turning them into movies might be a foolish gamble nevertheless. 
Ha! I was going to post that I was once channel surfing and I remember seeing on the Syfy channel a D&D movie that actually adhered to the rules of D&D pretty well but had no idea of the title or how long ago it was. This must have been it.
There was also a direct to video animated adaptation of Dragonlance’s first novel that would fit the requirements of the OP.