I was able to run this module in 2023 and I have the following things to say about it:

It's an AMAZING sourcebook for monsters, NPCs, encounters, towns and dungeons. If you buy this book you'll never need to roll up a random NPC ever again. You'll have a full book of ready-to-go encounters complete with spells, stat blocks and equipment. It's absolutely amazing.

The intro dungeon is great, but everything after that needs a lot of conversion in order to work. The Crater Ridge are absolutely MASSIVE and I had to throw half of it out completely. If you try to run this adventure as-written, be prepared for a slog. I recommend picking the parts that look cool and throwing the rest out.

The new monsters, magic items, classes and domains are great. This book is packed with great stuff.

In conclusion, it's an almost mandatory sourcebook for 3rdedition. It's essentially a Monster Manual, Magic Item Compendium and NPC Codex all in one.

A classic in every sense of the word. Does a terrific job of updating the original module and making it play in a totally new way.

I've been manually adapting it to 5e to accompany the flawed Princes of the Apocalypse model, and it has acted as an excellent complement to that particular module. Some deadly combats, some memorable NPCs, and an overall brilliant dungeon crawling adventure.

If your Pathfinder 1e/D&D 3.5 group are complaining that the campaign is too easy and/or simple, this campaign-tier module is more then enough to rip off those training-wheels and give the player group what they asked for and then some.

It's an absolute tragedy that this isn't Print-On-Demand much like it's Advanced 1e predecessor, hince why I'm giving it 4 stars

A must play it is a bit long though. I suggest skipping most of the town bull crap and just fill the player with the story and info and items. Saved us about 7 sessions time.

The 3rd edition update to the classic Gygax intro adventure.

Return to the The Temple of Elemental Evil has a new generation of characters returning to the Village of Hommlet (where time seems to have stood still) to investigate the new uprising of evil. Designed obviously to appear to adults who were kids when the original T1 and ToEE came out, it looses none of it's appeal.

Regardless what version of the game you play, if you ever played the original ToEE then pick this up.
If you have never played or run the original, but are a fan of the 3rd game, then certainly pick this up.

This is one of those adventures that should be republished for every edition of D&D. Great to start with and run some 1st level characters through but dangerous enough to merit coming back to at a later time.

Besides who doesn't want to go up against ultimate evil, stare in into it's ugly face and say "come get some!"