All of them look like they are tilted slightly to the left. I use things that should be plumb to 'level my horizons'. Things that give it away in this case are fence posts and corners of buildings.
The first three could definitely be cropped tighter (much tighter on #3) and I would probably try to correct the colors on those as well. It seems to me they have a greenish cast from the type of lights and the way they cycle.
On the first shot, I would try to lighten up the space inside the running back's helmet to see if I could illuminate his eyes.
In short, basically the shots are OK. They just need some more attention to detail in post processing.
I have an awful time shooting sports at night. Could be the same dismal lighting at the local fields or maybe it's just me.
Regards,
Jeff
Canon 20D w/grip, 300D, Powershot SX100 w/HF-DC1 flash, Canon 70-200 f/2.8L, 85 f/1.8, 17-55 f/2.8 IS, 50 f/1.8, 580EX and some other stuff...