I like the starry design, and the special corners add an interesting dimension. The corners aren’t that hard, either, once you understand how they’re constructed.

Personally, I have much more trouble with the extra-long double crochets and puff stitches than with the corners. It’s just not that easy for me to get a consistent height for every “stretched” stitch-- especially when they’re worked in the front loop only…

(Confession: I kind of hate making these “stretched” dc. They may look nice-- better for some than others-- but I don’t find them pleasant to crochet.)

I decided to rip back a couple of rounds and replace the stretched dc with tr and hdtr. Here’s what worked for me (though tweaking may yield better results for others):

10: tr
11: hdtr
12: tr
13: hdtr
14: very slightly “stretched” hdtr
15: hdtr

This slightly alters the look of the finished square, but I think it still makes an attractive block, and it was more enjoyable to crochet (for me), which is worth something, too.

(Corner-joined.)