That's a breath of fresh air on a Monday. The theme is explained nicely at 61A: Babies (aww ...) ... or an aural hint to 18-, 32-, 39- and 57-Across (CUTIES). Each long answer is a two word phrase whose initials are QT. They're all solid phrases, although QUARTERTONE is a bit out there for a Monday theme answer. And are 36D: Actor's prompt (CUE) and 65A: Blow away (AWE) sneaky additional thematic material?
3D: Creature that attacked the Nautilus in "Twenty Thousand Leagues Under the Sea" (GIANTSQUID) and 29D: Italian blue cheese (GORGONZOLA) are really outstanding long down answers. I also enjoyed 4D: Tree whose name contains all five vowels (SEQUOIA), almost enough to make it my favorite answer of the day.
The rest of the fill is fairly strong. I never like UTAHNS, and ADEE and ETTE are the kind of glue Jeff Chen likes to say are necessary evils. There's nothing I really hated. I enjoyed AQUA/LUNG, even though it wasn't referring to the Jethro Tull song. GINNIE Mae fooled me: I wanted faNNIE, of course.
1A: Game in which to cry "You're it!" (TAG) is saved by the liveliness of the clue, so I'll give it a C+. And my favorite clue-answer pair was 22A: Band aide (ROADIE). I love the lack of a question mark, certainly not needed here.
Thumbs up from me.
Not quite double Colum's time.... I didn't even notice the errors until reading the review above because I wrote "faNNIE" in right away and never bothered to check the downs, although 51D French playwright Jean (GENET) is not known to me. ICaNESS is, however, not a thing, and had I looked at it I may have noticed the problem. Regardless, this was a nice Monday, being not too easy to be uninteresting and having a well-executed theme. EGESTS is gross, as is TRUSS. LAYLOW could have referenced the more poetic way to discuss offing someone, but all-in-all I have to agree that SEQUOIA, and its clue, make up for any shortcomings.
Same mistake as Huygens. Never looked back, but did not get the music. And the GENET cross is brutal.
Much of the good has been covered. Is UTAHNS really a thing?