Great photos man, I really dig the first one and think it would look a better on a whole new level if you cropped it so that the skyline is the main feature in it. I feel the water's a tad distracting and that the skyline would probably look absolutely fantastic if you burned in the middleground to have more contrast against the background and cropped it so that the water is a less prominent element.
The second one looks great as well with the fast shutter speed although I'd like to ask if it was possible to have a faster shutter speed. I've photographed small waterfalls before and it was usually pretty hard to get a good shutter speed to capture the individual drops of water without them blurring too much.
The third one garnered a good amount of my attention because I especially like night photography, having seen a lot of photos of night scenes in Japan. It must have been extraordinarily bright in the particular scene you have there since the people aren't blurred out that much at all, in fact they're standing almost perfectly in place. I feel this photo would get a lot of good from having actual color on it; shop signs add so much vibrance and depth to night scenes, and desaturating it really removed a lot of the potential quality. Usually I'd reserve black and white for photos that focus well on shadows, midtones, and highlights, as well as excellent composure, but for this one I think would work so much better in the original color. Here's a pretty good photo of street signs in Shinjuku, Tokyo -
http://www.flickr.com/photos/manganite/391469293/
The fourth one I actually don't have much to say except I like gates. Except that, I think the composition would work a lot better from a different angle.
Anyways, really nice shots, they could work a lot better with some editing, and as always a general rule of thumb is that most photos captured with auto functions should be edited for a lot more contrast. Always try to aim for black blacks and white whites without overkilling it. Looking forward for future shots from you! (:
