I love the game demo. It is so good. Reminds me of old Lucasarts Adventures and not that cr*p that some companies call adventure these days.
On the gamepage it says the Demo was a preview of the first 4 hours, it took me only 1 1/2 hours to finish. How long will the finished game be?
Hmm maybe I missed something. Gonna replay and see.

It might not be first 4 GAME hours. Notice at the start how we cut back to 60 hours before the event? Ed is worked up at 6 am on a Sunday. At the 4-way split, we see events up to at least 7:30 am. Then arriving at the labs, it could be around 10 am when they find Dr. Morales. I think that's what is meant by first 4 hours. That means at least 56 more hours to play through, or perhaps more...

Sorry, slow reply here! It's very hard to measure gameplay time in an adventure game, especially a sizable and complex one like this. Some people will get stuck in places that others won't while some people will follow walkthroughs. Some people will skip through most of the dialog while some people will take the time to explore every optional puzzle and talk to characters about random STMs.

That being said, someone at GoG called this four hours based on their own first-time playthrough. I can play it in under an hour if I skip all the dialog!

There's a lot more game to come after this, but it's hard to say how long it will take each player. I can play through the entire game in about five hours by rushing through and skipping most of the dialog. On a normal playthrough, when I'm playing for enjoyment, listening to the voice acting, and covering most of the optional stuff, it takes me around 12 hours. If you're not me and you don't already know all the solutions to the puzzles, it should take you longer than that!

Hope that helps answer your question! Sorry I can't give you a specific number!

Just adding my own 2 cents.

We do tend to measure things on size, price, duration and other attributes... hell, it's our analytical way to compare things. Like everyone else, I also do that.
But let us all just keep in mind that pleasure or fun are not all about length (pun somewhat intended)... some things last only some brief seconds and are awesome! :)
I think you said the most important thing in the first paragraph, arschkrampi.

And I also did kind of felt that IJatFoA adventure vibe from it. Pretty cool :)