You guys both look like decent players. Assuming you are the one in blue, your game is similar to how I feel about mine. Many of your problems are based on footwork. Part of this is fitness related as you mention. Part of this is because you often pause for a moment and watch your shot before you start to recover. This snowballs into being a little out of position for many shots. Before you know it, you aren't keeping the rally going long enough to win and feel like you are giving up easy points.
This is even worse when you play someone that makes you run. I noticed that the guy in red was hitting a lot of good angles. When I really concentrate on footwork I tend to play much better (duh..). I have a hard time keeping this up as I don't play nearly as much as I would like.