I think that I review code much differently than the author. When I'm reviewing code, my assumption is that the person writing it has already verified that it works. I am primarily looking for readability and code smells.
In an ideal world I'd probably be looking more at the actual logic of the code. However, everywhere I've worked it's a full time job just despirately trying to fight ballooning complexity from people who prioritize quick turn around over quality code.