you can customise raiden, with the points you get from cutting mo-fo's up you spend on item upgrades and part upgrades, its a pretty awesome system.
And when you defeat a boss you can buy there weapon (blade) and then swap it out for your main weapon the same way you swapped sub-weapons in the demo.

Also, you can get custom body parts, I'm going to assume this is where the DLC is accessed and that the Grey Fox skin is a body customisation.. but becasue thats not on the PSN store i can't show it, but I can show this;