Regardless of the quality of the game, do you have any favorite adventure game box art cover?
I would include in the category also the original “cleaner” designs that were used for the box cover and also those designs that were shared in digital form but never used for a physical box.
I love a few of them, here is the first one that comes to my mind: Machinarium:
This
End of topic, I guess…
I was tempted to post that one, not because I played the game but because I’m a fan of Giger’s art. I even went to visit his museum in Gruyères. 
Oh I haven´t played the game either. We had a copy but that was those days when like every second or third game just wouldn´t work…
I envy you for having seen that stuff in the (biomechanical) flesh. I think the best thing I have ever seen out of things I really ever wanted to see is one Francis Bacon in munich.
Among Lucas* games, my second most favourite box is Loom™, because of its glowing effects, colors choice and simplicity.
Obviously this one 
Ahahah well… back in the early '80s, my father gave me the Mattel Intellivision consolle, and I spent many many hours with the following game, and loved that box:
This is off-topic, but you may be interested to know that there is a thriving Intellivision a enthusiast community over at AtariAge, where some of us are trying to keep the console alive, playing the old games and making new ones. 
dZ.
P.S. That reminds me that Mr. Keith Robinson, the current owner of the Intellivision Productions, Inc. properties and original Mattel Blue Sky Ranger from the 1980s, passed away this week. May he rest in peace. 
I was sure that you were about to suggest that cover! 
Indeed, it is one of my preferred ones and, more generally, I love most of Steve Purcell art. And that of course reminds me of…
Not pure point and click, but I remember the fantastic Roger Dean covers in the old times with my Commodore Amiga 500.
I actually wanted to mention this already on the non Lucas Arts Adventure games thread but have always been hesitant because it´s not really an adventure game but Exile has always been near and dear to my heart. From it´s ridiciously realistic physics, to it´s dark atmosphere, the sounds and colorscheme of the C64 and it´s early Metroidvania like gameplay (with a setting undoubtly inspired by that 1986 Nintendo hit set in the depths of a dark planet). Unfortunatly I never got really far and not even anyone on youtube could be bothered to play the C64 version to the end. Very underrated fun but really difficult game.
And I posted it here because I like the cover art that also reminds me a bit of a poster from an italian horror movie.
The Secret of Monkey Island
LeChuck’s Revenge
They are hand-made, very expressive and full of details.
Hmmm… the links are broken.
Fixed. Thanks!
Actually, I ought to add the cover of Zak McKracken to my list. Steve Purcell was an exceptionally gifted cover artist back then!
Want your mind blown about the Zak McKracken cover artwork?
Look at this:
On the Wikipedia article about Zak it says:
The original poster cover of the game mimicked the original Lucasfilm’s Star Wars poster; with Zak as Luke, Annie as Leia, while the Broom Alien as the Droids.
Another one of those things I never noticed back in the day.
…“copyright 1988 Lucasarts”.
Bullshit (cit.) 
Now it’s copyright Disney.
And back then it was Lucasfilm, anyway.
That’s not a surprise to me.
Believe it or not, I actually thought about this particular Star Wars poster when I was writing my comment above. It’s also one of the best cover arts I’ve ever seen. If it was a game instead of a movie, I had listet this poster as well.
By the way, I love such over-dramatized kitschy portrayals! It’s an element that Steve Purcell seems to have copied, too.
