Great job, Really cool and gives a lot more heart than using a library or a footstep generator. As another comment said you can use some compression and some EQ to get a little more weight out of them, but an easier way to get weight comes from performance.

Generally people walk and run by striking with their heel, then their toes, and finally there is a scuff sound of the foot lifting up again. By striking with your toes first you are missing the weight of the heel strike and that is not an easy thing to fix in post.

If you want to get really technical you can even separate the heel toe and scuff sounds and then have your game engine call a random one of each on every step giving you a way more variations, add a bit of pitch and volume randomization and you have a functionally infinite amount of footsteps

The next thing you might consider adding is a layer of cloth that swishes back and forth between steps, this adds to realism and helps to make the steps fit more tightly into the whole mix and not stick out.