Forewarning - I am not an expert on photojournalism, so I will comment to the best of my ability.
My first impression is that this works well for the challenge. It gives the feeling of being in the masses documenting what is going on. You get a strong sense of the crowd and even if these were the only people present you give an idea that there are many, many more.
I really like how the red colors stick out. Most everyone is wearing black or dark blue clothing and the reds shine out nice, both in the flags (ok the orange too) and the various articles of clothing (the red cross on the bottom and the red on the older ladies shirt in particular). The colors in general just work very well for me.
I am not really sure how to comment on improvements. There does not seem to be anything that really sticks out to me as being \"wrong\". I could see this pic being one of a series with other close up shots of some of the demonstrators. I think you have a really nice shot here and a great score to go with it (Anything above a 6.0 is great in my book). Well done.