Can't remember a tougher Thursday! I was still hitting my head at the 30 minute mark. Such a relief to figure out that STUMBLING ...
read moreCan't remember a tougher Thursday! I was still hitting my head at the 30 minute mark. Such a relief to figure out that STUMBLING BLOCKS were interpreted as ER hidden inside four black squares. I've fixed up the database answers and added ERs (in white) below to make things more clear.

Check out all the interlock. I'm usually not one to be impressed at themer crossings, but there's so much of it I could barely get my head wrapped around it. I highlighted all the theme answers (in blue) below to give a better picture of it. Granted, Tim did have a lot of flexibility because there are many phrases/words starting with ER, but wow. Audacious construction.
I would have liked all the short themers to be more solid, though. NETH(ER), DIN(ER), CHATT(ER), (ER)ROL, (ER)ASURE are all fine. (ER)NES, SHO(ER), even (ER)IE PA felt weaker. Tough to do, especially since there aren't nearly as many words starting with ER as there are ending with ER. Perhaps a little less interlock would have facilitated better short stuff like (ER)IN, (ER)OS, (ER)DOS, etc.
As if his task wasn't hard enough, the grid layout — featuring shorter answers — meant that he had to work in a lot of long fill. AXIS OF EVIL is colorful, and HYGIENIC is pretty nice. ULTRAHOT feels slightly made-up, like ULTRA NICE or ULTRA SMART or something.
ANNE SEXTON doesn't get as many Google hits as I'd like to see (500K), but I'd argue that winning a Pulitzer makes you crossworthy. I'm not wild about that final N though, crossing ASANA. ASANA is a yoga term I see all around Seattle (we're a yoga town, but I think that crossing sets up too many solvers for a pure guess. For a puzzle that's already ultra hard (ha) to solve, I'd want to make more sure that people who stick with it are properly rewarded.
It was tough for me to remember which black squares were the ER ones, so it would have been nice to have them distinguished somehow. How cool would it have been if those four squares were somehow made to look like they were stumbling! Not sure how to do that, but fun to think about.