Not all reviews are created equal.
There are many types of review. They have different intentions and require very different amounts of input.
Consider these questions when thinking about what kind of review you are going to do.
Organisations such as The Cochrane Library or The Joanna Briggs Institute have very detailed specifications on how a systematic review should be done (see Systematic Reviews - Resources tab). Consider whether you will be able to meet these requirement.
See the types of review tab for more information.