It's not often that I scratch my head, trying to figure out a puzzle's theme. Obviously JOHNNY ON THE SPOT refers to Johnny CASH, Johnny CARSON, Johnny BENCH, Johnny ROTTEN hidden in themers. Nice that all of them are Johnnys, not Johns.
But what does that ON THE SPOT refer to? I spent a good 15 minutes scanning the grid, trying to see if CASH was sitting atop the word SPOT, or a type of spot, or a black square representing a spot, or something else. The clue says "literally," right? It doesn't look like there's an additional layer that I'm missing. But it feels like there should be, darn it!
Nice set of famous JOHNNYs, all four with last names that can be hidden in phrases. I liked BENCH PRESS and ROTTEN EGG a lot, and CARSON CITY is pretty good too. CASH MONEY is a real phrase, but I don't hear it that often, even working in the world of finance. I might have preferred CASH CROPS or CASH FLOWS.
Interesting selections for long fill. I hesitated in filling in FANDANGO, because I only know it as the movie ticket site. Apparently it's a Spanish dance usually accompanied by castanets. I enjoyed learning that.
As for short fill, tough to start a puzzle by hitting AMO, SEN, ADLAI, ASCAP, ALG, all in one corner. Running ONSLAUGHT through two themers does make filling more challenging, but all the glue is a high price to pay, especially when the rest of the puzzle is dotted with CEE, EDINA crossing ENERO, ADEE, UNA, HORS, etc.
KOD looks so funny, but I like it. KO'D is common enough.
There's a high theme density here, what with five long theme answers, so that explains some of the gluey bits. Perhaps I really did miss some extra layer of theme? Andrew's too good of a constructor to let all the gluey bits through without a good reason.
ADDED NOTE: In fact, I didn't spot (pun intended) the ADs, i.e. advertising spots, under the various Johnnys — I've highlighted them below. D'oh! Thanks to all who pointed this out. Makes a lot more sense now; that adds a lot of difficulty into the already theme-dense construction.