Answering my own question, I finally (after sending an email to a couple of people in the "Contact Us" page of the Kappa web site) got a reply that they couldn't use any of my puzzles, and stating "Unfortunately, I am accepting a very limited number of puzzles these days, and after reviewing yours, I am going to decline. They are all solid puzzles, but I have to be extremely selective about the ones I accept." There was no indication of what type of puzzles they're looking for nor any indication of why they couldn't use these. Would be interested in comments from others - trying to determine if it's worth the trouble to submit any more.