1. It probably makes little difference, but my submitted clues for the five theme entries represented a multimedia smorgasbord: a record album, movie, book, comic book and TV show.
2. I like Will/Joel's clue for RADIO: Medium for Biggie Smalls.
3. A Roman numeral bridges two words in each entry. It's a bit different for CATWOMAN, being just one word. But since it's a compound word with the Roman numeral bridging the two word parts, that felt the same to me.

And, for anyone who hasn't already heard me blab about it, here's a book I created for kids — with a super-tough puzzle hidden in it for adults!

Neat idea, requiring two steps to figure out what was going on. After uncovering the IV in the central themer, I had a feeling Roman numerals were somehow involved, but it was a neat a-ha to discover that IV was interpreted as FOUR, which is part of FLAGS O(F OUR) FATHERS. Sort of a multiple-square rebus in a way, but also sticking to the usual one-letter-per-square criterion. I can't remember seeing something quite like this since Francis Heaney's incredible FLAG DAY puzzle, so I really enjoyed the novelty.

I've fixed up the database entries below, so you can see exactly what the themers are, post-decoding.

Because the idea was so interesting, I liked getting five themers, each one a treat to figure out. It was nice that Patrick managed to work in a little bonus fill too, TRUE GRIT being an incredible movie (and book — highly recommended!) and PELICANS pretty colorful too.

I would have liked more order in the themers, though. While having a random set of numbers (not in sequence) does make the puzzle even more challenging, the idea of going from I to II to III to IV to V (in order) is so appealing. I suppose THREE is a pretty tough string to incorporate into a phrase, as is FIVE. Even having random numbers but going in ascending order would be nice.

I also would have liked the four corners to be less cut off from the rest of the puzzle. The NW and SE are better, since two answers flow into each, but the top right and the bottom left have only one entry in. Although I love AZIZ Ansari ("Master of None" was a surprisingly moving series), I can see how that corner, especially the crossing with ZZZ, might cause some solvers to get really stuck and frustrated. Interesting fact that [Last entry in the Random House Unabridged Dictionary] is ZZZ — "a representation of the sound made by somebody sleeping or snoring, often used in cartoons." Curious that it's actually recognized as a word!

Loved the concept here, and as with most all of Patrick's puzzle, strong execution. Very enjoyable trick to uncover.

ADDED NOTE: Patrick mentioned that he had a different "order" in mind — one "trick" square in the first themer, followed by one, two, two, and then three. Clever idea; lulling the solver into thinking that maybe there was just a normal rebus going on.