great to hear that you found this application! In addition to my work on AcousticBrainz I also work at the Music Technology Group and was involved in this project.
We downloaded items from AcousticBrainz and made our own search database in order to be able to search by genre or mood. The source code for the application isn’t open yet, but I’ve just spoken to my colleagues and we will open it up soon.
What bugs do you see in the application? We will try and fix them.
We have future plans to offer search like this in the main AcousticBrainz API for the entire catalogue, but this is a new development project which we don’t have a lot of time for at the moment. We still have a number of other features that we want to finish first. Are you are developer? We’d love to have help on the project!