Most of your efforts reviewing the app should focus on completed features. A feature in progress may have bugs that have been noted and possibly fixed since you had the chance to test. If a feature has been marked as complete and it falls short, it’s best to provide that feedback as soon as you can.
The beginning of a project is the most difficult portion of a new initiative for many of our existing clients. The options that modern development can offer have so many potential applications that they are often difficult to turn into an actionable set of features when approaching a new initiative.