There is that story where the Gman tells you it's been ten years.
And we know that Breen knew Alyx when she was "just a little slip of a thing".
They put 20 years on the Episode 1 overview? I wasn't aware. Okay, then.
As for the actual building there are two texture sets for the walls: one worn away and one less so. In the palace_01 screens you can see it's more worn-looking, but I might switch that around. We'll see.
Alyx's age may also be a key to the elapsed time, but we don't know for certain when Eli's family picture was taken. We know from Kliener's noticeboard that Alyx was only small when she first knew him
And we know that Breen knew Alyx when she was "just a little slip of a thing".
But it isn't like they are going to stick two decades on the Episode 1 story overview if it's wrong.
They put 20 years on the Episode 1 overview? I wasn't aware. Okay, then.
As for the actual building there are two texture sets for the walls: one worn away and one less so. In the palace_01 screens you can see it's more worn-looking, but I might switch that around. We'll see.