The biggest difference between Maniac Mansion and the other Lucasfilm Games / LucasArts (Games) games is that Maniac Mansion does not have labyrinths.

Play almost any other game, and you will have frustrating (and artificially game-lengthening) labyrinths to deal with. The main reason why I never completed Zak McKracken and the Alien Mindbenders all that many times, only maybe ten times or so altogether. Indiana Jones and the Last Crusade is absolutely halted by these things (but that game fails also because of the forced action sequences that shouldn't be a part of an adventure game, except optionally, perhaps).

Heck, even Loom has them! I think Day of the Tentacle (a sort of 'sequel' to Maniac Mansion) is the only other game that is free of this annoying curse - and it is Maniac Mansion-related..

I don't mind some dead-ends (I think Zak McKracken and the Alien Mindbenders is way worse when it comes to these things - I really have hard time racking my brain trying to come up with Maniac Mansion-specific dead-ends, as I never suffered from them, during any of the numerous times I completed the game, or even before), if the game at least has the courtesy of giving me a glorious absence of labyrinths!

Ironically, the pre-SCUMM-game, Labyrinth, also has them.. how Maniac Mansion escaped them, when practically every other game suffers from them, I really don't understand, but THAT is a much bigger thing to me than the supposed 'dead-ends' that people keep raving about.

And the atmosphere, everything happening in a mansion, the beauty and genius of the graphics, the perfect sound effects and the general 'wackiness' (you never -quite- encountered it in this level, before DOTT, in which, it just felt cartoony and perhaps forced. I mean, in DOTT, the whole game is one big 'whack', when Maniac Mansion at least can be taken seriously for most part), the Extra-Terrestrial contacts (even DOTT didn't dare bring this back) and general 'anything exciting might happen' feel of the game more than make up for some small 'dead-ends'.

I think 'exploration' should be exciting in a game, and Maniac Mansion succeeds in this. The other games are more like following a linear story of a movie or cartoon, than pure exploration that exists in Maniac Mansion.. exploring a huge mansion is just something you can't replace by some jungle or city location that have annoying puzzles that you have to solve to arrive at the next boring location.

"What's behind that door.. " is the driving force that makes you solve the puzzle of how to get the door open, and the feeling when you first enter a new room - ah!

It  just can't be matched by walking in a generic street or a generic jungle scenery, getting some chest open or being able to enter some boring ruins because you finally tricked some monkey to hang on a branch.

It may be 'funny' or 'clever', but it's not going to make the player feel excitement or give the player a real sense of exploration, like Maniac Mansion with its mysterious and quirky rooms did. You never knew what the next room would look like, and it was always so different from what you had seen before. And every room was interesting, atmospheric, exciting or had some kind of subtle immersive presence about it.

Some daytime beach is never going to have the same impact.