Here is what Chris provided us about this challenging puzzle:
Gary, thanks for the email. Gotta love that I find out the publication date from you (though I'm sure I'll get an email from Patti and/or Rich any moment now). Curious to see what clues of mine they kept, but I guess I'll find out in a week or so.
Quick notes on this puzzle: I wanted to make a stagger stack of some entries that I liked and had been wanting to use for awhile. Originally started w/ YACHT ROCK (one of my favorite genres of music), NON-BINARY, and ARYA STARK from "Game of Thrones", but in trying to open up the middle and work in long answers through that stack, switched it to TONY STARK. Wasn't a fan of TTS (and neither were Rich and Patti) but it was worth the rest of the down answers through the middle.
I had some options in arranging the black squares at the top / bottom of the grid after that; I though about breaking up those areas into two corners each with three squares coming down (e.g. where TBS or ARI is) but liked the idea of having fifteens through there. Needed a few cheater squares to make those larger corners work, though I'm happy with the results throughout, even with some iffier short fill. But I particularly like the lower right, which has a lot of personal flourishes and flavor that I like.
Chris's puzzles always have some fresh, contemporary items and that keeps us all learning. My last fill was the R in TONY STA_K/PETER A_NO. CHOOSING UP SIDES was my first long fill. Its twin TRIGGER WARNINGS was a new phrase for me but pretty easy to suss.
1. Sony videocassette brand developed in 1982: BETA CAM - When these two formats came out, I chose the wrong one
8. Wedding memento: ALBUM.
13. Wide-brimmed hat: SOMBRERO.
14. Plunder: BOOTY.
15. Making teams, in a way: CHOOSING UP SIDES - Getting picked last is one of the real traumas of growing up
17. "Out of the Cellar" rock band: RATT - It's a hoot when anti-establishment groups of years ago are now making commercials
18. Hit the gym, with "up": TONE.
19. Last ruler of the Julio-Claudian dynasty: NERO.
20. Organisms that move via pseudopodia: AMOEBAS
23. Sporty Audis: TTS - Chris's reluctant fill
25. A show may have a long one: RUN - Until COVID-19, Phantom Of The Opera has been RUNNING on Broadway since 1988. No Broadway shows will reopen until at least Jan 3, 2021
26. French pointillist: SEURAT - That's a lotta points!
27. Cookout options: WEENIES.
29. Honolulu setting: Abbr.: HST - The Japanese Zeros first appeared around 8 a.m. Hawaiian Standard Time on the date that will live in infamy
30. Genre originally called the West Coast Sound: YACHT ROCK - Kenny Loggins, et al. The definition and 17 examples
32. Gender identity spectrum: NON-BINARY - Ruby Rose is said to be "gender fluid" and can wake up any day as male or female
33. "I am Iron Man" speaker: TONY STARK - A role played by Robert Downey Jr.
34. MLB "twin killings": DPS - Double Plays are called a "pitcher's best friend"
37. Involve deeply: IMMERSE.
38. Exclusive MLB cap supplier: NEW ERA - A NEW ERA Washington National hat online is $39.95. I bought mine from a street vendor across from Ford's Theater for $9.95
40. Med. insurance plan: HMO.
41. ["Is this thing on?"]: TAP.
42. Wave that maintains its shape and speed through collisions: SOLITON - Gee, Gary, I'd love to see a 3 min video about this. Or not...
43. Swedish pop band: ABBA - Let's see, our names are Agnetha, Bjorn, Benny and Anni-Frid. What could we call our group?
45. Peter of reggae: TOSH - His website
47. Advance: LEND - Did you ever ask for an advance on your pay/allowance
48. Alerts about potentially disturbing content: TRIGGER WARNINGS- Someone with PTSD might need such a warning before watching a movie like Full Metal Jacket
52. "Elements of Algebra" author: EULER - Here's another one of his page turners
53. Emulate a bookie: TAKE BETS.
54. Dodger Pee Wee: REESE - This statue in Brooklyn commemorates Kentuckian Pee Wee REESE's support of Jackie Robinson in his first major league season
55. Sneaky programs: SPYWARE.
Down:
2. Glowing star, say?: EMOTER - Stella!
3. "Full Frontal" network: TBS - A Samantha Bee show
4. NL West team, on scoreboards: ARI - The Fenway scoreboard shows that the ARI - COL game had not yet started
5. Pair in a view?: CENTS - I love this! When you express your view, you are putting in your two (pair) CENTS worth
6. 2012 Affleck thriller: ARGO.
7. Hephaestus' workshop was said to be under it: MOUNT ETNA - Here ya go! Okay, not all of Chris's references are contemporary
8. Pilates targets: ABS.
9. Butcher buy: LOIN.
10. "10" co-star: BO DEREK - OMG, that was 41 years ago!
12. Last words of Kipling's "If": MY SON
13. Disgraces: SHAMES.
15. Computer problem: CRASH.
16. Longtime New Yorker cartoonist: PETER ARNO - I think the golfer is the only guy going in the right direction
21. Sharp weapon: BAYONET.
22. "Regardless ... ": AT ANY RATE.
24. Diving device: SNORKEL.
27. Wintry, in a way: WHITE - Things are so GREEN right now and not 28. Wintry, in a way: ICY.
31. Longtime Masters TV venue: CBS SPORTS - Until this spring it was a sure harbinger of spring
32. Snarfing sound: NOM
33. It acquired the naming rights for the former Safeco Field: T-MOBILE - 7 minutes south of the Space Needle
34. Cold War warm-up: DETENTE
35. Fine points: PRONGS.
36. Smooths, in a way: SANDS.
37. Saturate: IMBRUE - Definition
39. More cunning: WILIER.
40. Twitter malcontent: HATER.
42. Unstable: SHAKY.
44. Rusts or grays: AGES - My hair is acquiring the latter
46. Quid pro quo: SWAP.
49. Its General Test consists of six sections: Abbr.: GRE - One of several test acronyms used for cwd fill
50. Fire TV button: Abbr.: REW - Sometimes, no letters no just arrows
51. Kawhi Leonard's org.: NBA - He went to Toronto for one season, got them a championship and then left for the LA Clippers. He turned down a huge salary, free housing and free groceries Toronto offered him to stay.
How 'bout some comments for Chris:
