The pair carried over a limited number of elements from Maniac Mansion and forwent the character selection aspect to simplify development.

Day of the Tentacle has featured regularly in lists of "top" games published more than two decades after its release, and has been referenced in popular culture.

Bernard travels to the Edison family motel with his two housemates, deranged medical student Laverne and roadie Hoagie, and frees the tentacles.

To salvage Dr. Fred's plan, Bernard must acquire a replacement diamond for the time machine, while both Hoagie and Laverne must restore power to their respective Chron-o-John pods by plugging them in.

[14] To overcome the lack of electricity in the past, Hoagie recruits the help of Benjamin Franklin and Dr. Fred's ancestor, Red Edison, to build a superbattery to power his pod, while Laverne evades capture by the tentacles long enough to run an extension cord to her unit.

Eventually, Bernard uses Dr. Fred's family fortune of royalties from the use of their likeness in Maniac Mansion to purchase a real diamond, while his friends manage to power their Chron-o-Johns.

[16] Bernard and his friends defeat the Purple Tentacles guarding the Sludge-o-Matic, turn off the machine, and prevent the whole series of events from ever happening.

[19] In planning the plot, the four designers considered a number of concepts, eventually choosing an idea of Gilbert's about time travel that they believed was the most interesting.

Grossman noted the appeal of the need to make wide-sweeping changes such as the Constitution just to achieve a small personal goal, believing this captured the essence of adventure games.

[20] The game's other protagonists, Laverne and Hoagie, were based on a Mexican ex-girlfriend of Grossman's and a Megadeth roadie named Tony that Schafer had met, respectively.

[21] Schafer and Grossman planned to use a character selection system similar to the first game but felt that it would have complicated the design process and increased production costs.

[23] Looney Tunes animation shorts, particularly the Chuck Jones-directed Rabbit of Seville, What's Opera, Doc?, and Duck Dodgers in the 24½th Century inspired the artistic design.

Grossman cited cartoons featuring Pepé Le Pew, and commented that the gag involving a painted white stripe on Penelope Pussycat inspired a puzzle in the game.

Grossman and Schafer brainstormed regularly to devise the time travel puzzles and collaborated with members of the development team as well as other LucasArts employees.

[20][22] To complete the elements, Grossman researched the period to maintain historical accuracy, visiting libraries and contacting reference librarians.

Ahern noted that their previous games would run the credits over primarily still shots which would only last for a few minutes, but with Tentacle, the team had grown so large that they worried this approach would be boring to players.

Another LucasArts designer, Hal Barwood, suggested they cut it in half, leading to the shortened version as in the released game, and having the player take over when they arrive at the mansion.

[17][22] To aid the process, Grossman commented that the character should sound like Les Nessman from the television show WKRP in Cincinnati.

[26] The three had worked together to share the duties equally of composing the music for Monkey Island 2 and Fate of Atlantis, and continued this approach for Day of the Tentacle.

He enjoyed the game's humor and interface, and praised the designers for removing "dead end" scenarios and player character death.

Ardai lauded the voice acting, writing that it "would have done the late Mel Blanc proud", and compared the game's humor, animation, and camera angles to "Looney Toons [sic] gems from the 40s and 50s".

[40] Sandy Petersen of Dragon stated that its graphics "are in a stupendous cartoony style", while praising its humor and describing its sound and music as "excellent".

[41] Phil LaRose of The Advocate called it "light-years ahead of the original", and believed that its "improved controls, sound and graphics are an evolutionary leap to a more enjoyable gaming experience".

He praised the interface, and summarized the game as "another of the excellent LucasArts programs that place a higher premium on the quality of entertainment and less on the technical knowledge needed to make it run".

The writer praised the game's humor, and said that "both the music and sound effects are hilarious"; he cited the voice performance of Richard Sanders as a high point.

The editors wrote that "Day of the Tentacle's fluid animation sequences underscore a strong script and solid game play ... story won out over technological innovation in this genre".

[30] In 1996, the magazine ranked it as the 34th best game of all time, writing: "DOTT completely blew away its ancestor, Maniac Mansion, with its smooth animated sequences, nifty plot and great voiceovers".

[50] In describing what he considered "the most rewarding moment" of his career, Grossman stated that the game's writing and use of spoken and subtitled dialog assisted a learning-disabled child in learning how to read.

Though never officially approved, the game used a pseudo-3D art style and was nearly 80% complete, according to one person close to the project, but was shelved in the days before the closure of LucasArts.

[20] The game includes a more streamlined interaction menu, a command wheel akin to the approach used in Broken Age, but the player can opt to switch back to the original interface.