My first thought was that they are cropped a bit too tight for my taste. A face off involves 2 players, and for the most part, your cropping seems to focus more on 1 player.
This is really hard to pull off. First the lighting isn't optimum, it's coming down from the top, the players are facing down giving you dark faces (not there is much you can do about this). Second the first two pictures have a distracting background, which you managed to remove / hide in the last two. Lastly I would like a little more pop in the colors however it could be my laptop monitor giving this appearance, maybe I should have spent more money on the laptop instead of buying L lenses (NAH).