1) If you're going to do this shot this way, it needs to be perfectly centered, or completely off center. The 'kind of almost centered' look is disorienting. I would have also shot it at a lower exposure, to reduce the blown out portions, then borught up what I needed to bring up in post processing. If in doubt, shoot a little underexposed. It's easier to fix dark portions than blown out highlights. Also, I'd probably add a little contrast and saturation, as the main selling point of the image, in addition to the vanishing point and lack of people in a should be busy area is the colors, but they fall a little flat, IMHO.
2) Need more DOF, the front coco is out of focus slightly. also, you could use a little contrast and saturation. Not a lot more, but a little more.
3) Seems a little cool to me temperature wise. It also seems tilted int eh background, but that could just be the angle of the beach there. I like the composition a lot though. I'd have probably knocked the exposure down on this as well a bit, to get more vivid colors, and bring out detail in teh clouds, then brightened whatever needed to be brightened in post processing. You could also do with a little more contrast and saturation here, again, jsut a subtle amount would make it pop. The fort also needs to be sharpened at the turret a bit.