When people imagine code reviews, they imagine people analyzing code and haggling about coding guidelines. They are much more than that.
Code reviews are more about the meeting point and the excuse to talk about the software than they are about actually reviewing code. For projects less sensitive to bugs, my code reviews are not about trying to spot off-by-ones or buffer overflows. They are about discussing the problem, as perceived by the developer, possible mismatches between the developer's interpretation and the actual problem, the designed solution, how it fits the problem and how it fits the overall architecture, as well as the actual code.
The actual code review style can be as informal as an end-of-day five minute talk with each developer, all the way to the formal end-of-week review of work done. Have them fit your culture.
In the end, all that it matters, is: keep your team talking.