The movies have never been very clear on Riddicks power besides nightvision. He beat the Lord Marshall so he's stronger than a guy with Schrodingers probability powers that made him near impossible to beat. So I guess he's super strong? And he was the only guy who the Lord Marshall couldn't pull the soul out of, so he has soul powers. And he has really fast reflexes. And he can probably heal fast because he gets fucked up a lot, like he gets cut and he doesn't have any scars or anything.