Ok gotcha. I think you're asking a bit too much from them to give you personally tailored advice. Your interviewers most likely didn't even read your resume.

Ok gotcha. I think you're asking a bit too much from them to give you personally tailored advice. Your interviewers most likely didn't even read your resume. Most companies will just send you pre-formatted email "sorry you weren't a fit". If you're trying to parse their message "we're not sure you have enough practical experience programming - maybe try working on an open source project" then I would interpret it as I stated above - they didn't think you demonstrated the depth of experience that they were looking for, and were hoping that working on more types of projects, which you might not get at your job, but you might get by working on a whole bunch of different open source projects, might get you.