Player characters must survive the deadly traps in the tomb and fight their way into the demi-lich's elaborately concealed inner sanctum to destroy him.

[5][7][8] Gygax developed the adventure from an idea by Alan Lucien, one of his original Advanced Dungeons & Dragons (AD&D) playtesters, "and I admit to chuckling evilly as I did so.

[5] The module has been described as the first adventure of a high-level scenario series,[14] and was included as part of the Realms of Horror abridged compilation produced in 1987.

In 1998, the module was reprinted as part of the Return to the Tomb of Horrors module—a substantial expansion and sequel to the original adventure, written for 2nd Edition AD&D rules.

[17] The second Tomb of Horrors is a conversion and update of the original module for 4th Edition rules, written by Scott Fitzgerald Gray and released to members of the RPGA as part of the DM Rewards program.

[20] Lawrence Schick wrote in the foreword: "The dungeon of the demi-lich Acererak was, for Gary, a kind of thought experiment: If an undead sorcerer really wanted to keep his tomb from being plundered by greedy adventurers, how would he do it?

[22] 2018 special edition of the book Art and Arcana contained a bonus pamphlet of the "original 1975 tournament module" previously unpublished.

[23] As part of Extra Life 2019, Wizards of the Coast released Infernal Machine Rebuild, a time-hopping adventure that allows characters to travel back to the Tomb of Horrors during its construction.

"[7] Wayne MacLaurin of SF Site describes the module as "a classic" and a "must have" for gamers, saying that when he played the game in high school, most of his group's characters quickly died.

MacLaurin explains that Tomb of Horrors is a classic not because of its difficulty, but because it was the first module that did not involve killing large numbers of monsters; it was a "collection of puzzles and maps."

"[25] The authors of Dungeons and Dragons and Philosophy: Raiding the Temple of Wisdom commented that "One of the most famous D&D adventures, the Tomb of Horrors, has grown to have a legendary status amongst gamers [...] It has come to be known as a truly difficult adventure, and obtained enough of a cult following to induce some players to put 'I survived the Tomb of Horrors' bumper stickers on their cars.

"[27] David M. Ewalt, in his book Of Dice and Men, discussed the adventure's reputation as "the deadliest game ever written", noting that it "unloads a series of complicated puzzles and nightmarish traps" on characters, concluding that "Few survive long enough to collect any treasure, and even fewer manage to find their way back through the deadly maze and escape with their spoils.

"[28] Something Awful presented a humorous article about the ways that Tomb of Horrors is the bane of gamers everywhere since it is basically a series of traps that kills off most of the characters.

[30] The computer role-playing game Icewind Dale, developed by Black Isle Studios, was influenced by the module; Black Isle Studios division director Feargus Urquhart said, "We wanted something that reminded everyone of their first foray into dungeons like the Tomb of Horrors, with traps around every corner, and the undead crawling out of the walls.

"[31] Tomb of Horrors is key to the plot of the novel Ready Player One by Ernest Cline, which is set in a virtual reality world created by a man who was a fan of the module.