Welcome to the forums!
What I'm about to say about these photos should be taken as just one opinion only. Others, including you, may not see or interpret them in the same way, and in the end, only the opinions of you and your clients matter. So then, the way I see them...
1. Needs more contrast. It's dull, it's grey, it's boring. It's a cool sign. I've shot it myself. Punch it up to make the best of it using a curve adjustment or something. Probably needs a bit of sharpening as well.
2. The focus seems to be in the middle of the wall to the left, which is a leading line to the building dead ahead, which doesn't make sense to me. I think the focus should have been on the building dead ahead instead, especially if you're going to use f/4 on a shot like this. Also, my take on the composition is that the negative space to the right of the building ahead which then wraps up and over it does nothing for the photo. The interesting things are the buildings and the lines and shapes they make. That said, I think it would have been a better composition to turn slightly to the left to put the buildings edge at the right frame.
3. I like the composition for the most part, but feel like there's a lost story here because the old brickwork has a lot of detail we don't get to savor. Perhaps more contrast and sharpening on that will bring it out. It needs a bit of grunge, I think. It's also a bit soft through most of it. I see you shot it at f/4. I think a bit more DOF would have helped, like maybe f/11 or more.
4. This had potential, but the horizon through the center throws it off. I'd say crop off the top and as much of the right side as you can without cutting into the tower, then sharpen liberally.
5. The interest for me here is the perspective, balance, lines and shapes. That said, I'd be inclined to suggest that the composition is slightly off and would have benefitted from a slightly higher viewpoint looking down more to get the top of the wall's lines horizontal and at the top of the frame. f/8 seems a bit too shallow for this as well, putting most of the interesting stuff slightly OOF.
6. Love the tones. Not crazy about the building's top being cut off, and think it should all be included. Would also like to see it rotated to where at least one line in it is straight up and down - probably the far edge of the first set of windows closest to us on the left wall. Again, I think the concrete needs some grunge to bring out the essence of these old prison walls - selective contrast, curves and sharpening might do the trick.
7. Love the tones and the contrast. The composition itself leaves me hanging. 3 things or 5 things tend to work better compositionally than 2 things or 4 things, IMHO. All in all, just not terribly interesting, and doesn't hold my attention for long.
8. The escape route. A standard shot if you visit Alcatraz, but lacks much interest, especially after the whole world has seen it a bazillion times. Maybe a fresh perspective, say from down lower to the floor or something would give it more interest. The focus appears to be on the bed instead of the wall, and at f2.8, that misses the mark, putting the real subject into soft focus, which detracts badly from it. That area needs as much focus and sharpness as it can get, so that we can smell the damp, dank cell wall.
9. My favorite of the set. Still, the composition, IMHO, would have benefitted form not putting the corner right down the middle of the shot, aligning whatever line is in the middle straight up and down, and lowering the viewpoint slightly to get a little less vertical perspective (toeing in of the top).
10. The shot through the cage is okay, but I think not as strong a similar shot without the cage. It's just too distracting, to my eye.
11. Underexposed, too low in the frame (expansive sky with no features is uninteresting negative space in this one from my pov), needs sharpening. Not crazy about the centered island either, but not sure if moving it to one side or the other would really help it compositionally, unless there's something over there for it to play off of, and that depends on where you shot it from.
Sorry if that seemed harsh. Just giving my honest opinion, and in the end, it means very little, especially if you like them.
