I mean if it's a code review, you gotta review the code.

Yes, but code can be presented in different ways. This depends of course to a degree on the submitter (large changeset touching a lot of files or smaller change sets building upon each other?) but also could be presented differently (highlighting changes to data structures, identifying core parts of code and helper routines - lots of room for imagination)

Also mind: one doesn't only have to review changes code, but also review what hasn't been changed (are preconditions of other code still met?)