Just my opinion:
Arguably useless. You already have a masters in software engineering. Which is worth a lot.
Very important. If you want to put games on your portfolio, focus on small games that you can do alone or with a small team.
You could tackle different technologies with every project. So for example, use NodeJS for a server based project. That way you will not only show that you have the dedication to finish a project but also widen your horizon as far as programming languages are concerned.
See #2. Learning by doing is IMO the best way to do this.
As for the "meeting all required criteria" thing. From my experience employers will not immediately reject you if you can show that you are eager and quick to learn.
If I was an employer, the fact that you have a masters degree and some personal projects to show, would get you at least a consideration and invitation for an interview.
If you are not applying for a senior position you will probably be given a supervisor who will guide you while you are learning to be productive in the company.