Doesn't this one feel like it should have been yesterday's puzzle, and yesterday's puzzle should have been today's? I very much enjoyed this offering from Ms. Margolin. I see that this is her second accepted puzzle, according to X-word Info, and it looks like the various bloggers on this site enjoyed the first one as well. That bodes well for future efforts from this creator!
The theme is definitely hidden, and I don't know if I would have figured it out without the assist from the info button, which helpfully flashes at me when it has something to tell me. The word "game" is hidden in each of the four long across answers. We have two ancients of legend, GILGAMESH and AGAMEMNON, and two standard phrases, both well accepted. I would have preferred if the hidden word was split across the two words in both answers, as in MAKINGAMENDS, but I can see that might be difficult.
And then there's a second layer, in that each of the four corner across answers precede the word "game" in a standard phrase. For that reason, 1A is actually a theme answer, and I don't feel right giving it a grade. 8A: Watch it! (VIDEO) is sort of odd as a clue, but fine.
But it's the rest of the fill that make this puzzle delightful. I was surprised to see Wade BOGGS in there, formerly a Red Sox stalwart, subsequently a Yankee traitor and a Devil Ray. The long downs are excellent, especially THESHINING (nice that the "the" is included), DOWNUNDER, and DEARSANTA. GOLDMEDALS is only marred by the pluralization.
On the down side, EMAG reappears. I wonder if it is, in fact, a hidden theme answer? Read from bottom to top? That would be much more acceptable. DEADER is awkward. Otherwise I can put up with the rest.
My favorite clue and answer pair today is: 23A: One of Seuss's Star-Bellies (SNEETCH). I even appreciate the correct usage of the 's in the clue.