There are different aspects of the code that have to be considered when reviewing it. Primarily, the code being reviewed should only be the code that was modified by the programmer and submitted for review. That's why you should aim to make small submissions often. Small amounts of code are much easier to review and comment on.
Let's go through different aspects a code reviewer should assess for a complete and thorough review.
Company's coding guidelines and business requirement(s)
All code being reviewed should be checked against the company's coding guidelines and the business requirement(s) the code is addressing. All new code should adhere to the latest coding standards and best practices employed by the company.
There are different types of business requirements. These requirements include those of the business and the user/stakeholder as well as functional and implementation requirements. Regardless...