The search button with the black text on the gray/black gradient is kind of hard to read, but not illegible.
The sidebar seems to be overlapping the div that holds that banner and the breadcrumbs near the top (right side of the div's black border is missing).
Very minute, but there's quite a large white drop shadow on the up arrow in a quote block next to the user's name.
Content:
Perhaps condense the Ultimate Castle Defense category until you get enough content to merit that many nodes
Maybe have handhelds as part of Consoles (ie Consoles and Handhelds), same principal as above. Having too many empty nodes can reflect badly on your site
Thanks for the suggestions. I fixed 1 through 3, 4 is built into Xenforo. In fact you can see it in action on the default style on this forum. I used the style creator to make the color scheme, so rather than thick blue lines that the style on this forum uses, my style does thick grey lines.