Oh my Schruti, you are giving me some big questions about your career!

When evaluating if a masters program is right for you, research where the alumni are ending up. This goes the same for any learning program, such as design bootcamps. I actually took the job offer at IBM Design solely because of the free opportunity of a design bootcamp.

As for which field, I would scope the syllabus of classes in the programs to see if that is what interests you. If you go with game design, you are going to become a specific expert in that field. If you choose HCI, you are instead going to get some broad skills that help in a variety of situations.

I know I am not directly answering your questions. However, I hope this advice helps you really find YOUR answers!