- Overall project structure seems a bit unorganized IMO (no centralized build process, gulpfile inside subfolder). Overall this makes it fairly hard to dive right into the project. It might be my lack of experience in PHP project structure.
- I think pulling in a server & a db might be an overkill. Local storage will do the job perfectly.
- Mix of tabs & spaces is also very messy.
- Styling is pretty sloppy too I believe. No clear organization/reusability in the stylesheets.
- Vendor scripts/generated scripts should not be committed to the repo IMO. There're already bower & CDNjs & a bunch of other services.
- Your JS is also very module/singleton-based although some of them are clearly object-oriented. Also seems to be a mix of jQuery usage & DOM directly, why not 1?
I think what they're looking for is a couple of simple JS that's easily tested, maintained & expanded which IMO is more important for senior candidates. Less senior ones can always bang this out quickly but senior ones care way more about other attributes of a project than just getting it done asap.