No, I'm talking about the jagged edges of the bricks, players etc.
Now I think about it, can't I just use Anti-aliasing in Catalyst to make the edges look smoother?
Ooooooo.
I believe it might be antialiasing. I think Eksi uses a special brick texture pack too that makes the white lines on the bricks non-existent.
Its possible he might use some kind of video softening but I really doubt that. Definitely try and put your graphical settings on high, try anti-aliasing, and try the custom brick textures.
My computer also made the brick edges kind of liney and rough, almost certainly graphics options and graphics card.
Could be wrong, maybe someone else can confirm your idea.