You've got some basics down and it seems like you're comfortable controlling DK. Good spacing with the bair, although you seem to be depending on it too much as a poking move. The foot is more for knocking opponents off the edge and edgeguarding, although the way you're using it works too. Just cut back on it a little. Your biggest weakness seems to be that you give up grab opportunities way too much. Cargo uthrow --> a couple uairs = a dead Roy. Roy is also particularly easy to shield grab when he's not careful like your opponent was, and doesn't try to land outside your grabrange. You had lots of easy grab opportunities that would have lead to easy combos against a character like Roy who's at the perfect fallspeed to allow you to combo the crap out of him. Also, for edgeguarding, try a ledgedrop-upB. It works great against characters with predictable, straight-line recoveries like Ganondorf, Mario, and especially Roy since he's screwed the second you hit him with it. I only watched the first match, btw.
