This is a Sunday In-Out Slitherlink puzzle.
This puzzle was made shortly after I did the one posted here
by a Japanese author, whom I do not know although he apparently has seen this site. In my attempt to give feedback (albeit in English) on his post I was thwarted by a Japanese CAPTCHA, so apparently on Japanese sites I am indistinguishable from a spam bot. Darn.
To compensate, here is my shout-out and tribute to that construction. The main ideas employed aren’t that similar; I was mainly trying to put to thorough use a number of deductions that I learned while doing that puzzle.