Adaptation Displacement: It's a sequel to Maniac Mansion, but a lot of gamers didn't even know since the game itself never states this, despite making numerous references to its predecessor. Fortunately, the original game is included as a game-in-a-game in the sequel (by "using" Ed's computer), though folks emulating today with ScummVM need to put in a little extra work to play it.
Even Better Sequel: A child of LucasArts' golden age and it shows. Witty and ergonomic when compared to the original SCUMM game. DOTT is a very polished game which greatly benefited from the acquired experience of the designers, who averted several mistakes such as Unwinnable by Design. Maniac Mansion probably only bests it in one regard; multiple (and selectable) characters leading to multiple endings and adding Replay Value. The sequel is also Lighter and Softer, as it's less hardcore.
Hilarious in Hindsight: In the past there is a painting of Max in the 2nd floor hallway, and Hoagie describes him as a "patriotic dude". Fast forward to the Sam and Max reboot by Telltale Games, and Max becomes president of the United States.