His legs move as though the guy is suspended and kicking his legs. Don't be afraid to squish, stretch, noodle, and skew the limbs early on; it's more important to get the right energy and movement than cohesiveness at this stage. The forum is littered with more in depth comments about making an effective run cycle right now, so do some shopping around if you need to learn just how to get that movement. Also try running yourself; it helped me while I was doing my edit!
Three points:
His foot looks as though it's sliding along the ground for a bit in the instances right before and after the foot hits the ground. This gives it an almost zero gravity vibe, but it's an easy fix. Just make the contact with the ground more abrupt.
His feet move almost like a pendulum would, but his upper legs should be the only parts of his lower body that follow that path of movement. In a run, the foreleg is kept at about the same height all the way from the kick off to the contact with the ground.
Notice the little blue lines that I made below your character's feet in my edit. Notice a difference between the top image and the bottom one? I found that when I ran, my leg would anticipate my opposite leg's contact with the ground, and wait until that contact to spring forward really fast.
My really sloppy rough edit:
I hope some of this is useful!
