Thank you Basilisk. Some nice surfaces here. Definitions are underlined in the clues.
Across
1. Great role identified by diminutive actor? (6)
HAMLET : HAM(an overacting actor) – LET(a suffix signifying a small/diminutive version of something, a “booklet”, say).
4. Valuable piece that sums up Oxford University dons (8)
PRECIOUS : PRECIS(a written or spoken piece/account that sums up/summarises a text or speech) containing(… dons) OU(abbrev. for “Oxford University”).
10. Trace exclusive feature I found in shoot (9)
SUSPICION : [USP(abbrev. for “unique selling point”/an exclusive feature of a marketed product) + I] contained in(found in) SCION(a young shoot of a plant, especially one cut for grafting).
Defn: A hint.
11. Strange article about fake news? (5)
ALIEN : AN(an article in grammar) containing(about) LIE(fake news/a fiction).
12. Flag piece in The Observer (4)
IRIS : Double defn: 2nd: …, the sensory organ and not the Sunday one.
13. Finance centre‘s rule about disposal of letters (4,6)
WALL STREET : Reversal of(… about) LAW(a rule defining correct procedure in a sport) + anagram of(disposal of) LETTERS.
15. Force uses ill-gotten gains to control Congress (7)
GRAVITY : GRAVY(ill-gotten/unearned money/gains) containing(to control) IT(euphemism for sexual intercourse/congress).
Defn: In physics, the force attracting a body to one of (great) mass.
16. Gang member returned cannabis to staff nurses (6)
TSOTSI : Hidden in(… nurses) reversal of(returned) “cannabis to staff“.
Defn: From South Africa, a young urban criminal/gangster, especially one from a township.
19. New clubs split costs for professional security measures (6)
FENCES : [N(abbrev. for “new”) + C(abbrev. for “clubs”, the suit in a deck of playing cards)] contained in(split) FEES(costs for using a professional to provide services).
21. Relation’s about to go over to the other side in haunting image (7)
SPECTRE : RESPECT(relation/reference to, as in “with respect to/in relation to”) with its(…’s) “re”(about/with reference to) moved from the start to the end(go over to the other side).
23. A fine line divides romance and suffering (10)
AFFLICTION : A + {[F(abbrev. for “fine”) + L(abbrev. for “line”)] contained in(divides) FICTION(a romance/a make-believe)}.
25. Squeal as insect’s tail is removed from bite (4)
SING : Last letter of(…’s tail) “insect” deleted from(is removed from) “sting”(the bite of some insects).
Defn: To inform on somebody.
27. Take steps to administer beating and vanish (5)
TANGO : TAN(to administer a beating/thrashing) plus(and) GO(to vanish from/to leave the presence of).

28. Agreed with auditor’s intended compensation (9)
ATONEMENT : [AT ONE](agreed/in unison) plus(with) homophone of(auditor’s) “meant”(intended/deliberate).
29. Military location hosted individual (8)
PARASITE : PARA(an airborne unit of paratroopers in the military) + SITE(the location, of a building, say).
Defn: A living thing/an individual hosted by/latching on to another for food and shelter and usually causing harm to the host.
30. Commanding officer and company working in secure location (6)
COCOON : CO(abbrev. for “commanding officer”) plus(and) CO(abbrev. for “company”, a commercial concern) + ON(working/in operation, as with an electrical appliance).
Down
1. America objects after husband is promoted in election campaign (8)
HUSTINGS : US(abbrev. for things American/from the US) + THINGS(objects/items) with(after) “h”(abbrev. for “husband”) moved to a higher position(is promoted, in a down clue).
2. Make use of Jaws with international cast at sea in China (9)
MASTICATE : Anagram of(… at sea) [I(abbrev. for “international”) + CAST] contained in(in) MATE(pal/”china’ in Cockney rhyming slang, from “china plate”).
3. Lead character in extravagant film like The Greatest Story Ever Told? (4)
EPIC : 1st letter of(Lead character in) “extravagant” + PIC(short for “picture”/a film/a movie).
5. Characteristic sound associated with Rent and Hair (7)
RINGLET : RING(a characteristic/recognisable sound made by, say, a phone or a bell) plus(associated with) LET(to rent out a property).
Defn: … hanging down in a spiral curl.
6. Wife leaves educator who edited and wrote joint work (10)
COAUTHORED : Anagram of(… edited) [“w”(abbrev. for “wife”) deleted from(leaves) “educator who“].
7. Suppose authentication code is used instead of one’s name (5)
OPINE : PIN(abbrev. for “Personal Identification Number”, an authentication code in electronic transactions) replacing(is used instead of) “n”(abbrev. for “name”) in “one”.
Feels as if something is missing in the wordplay.
8. Holy state banishes court for good reason (6)
SANITY : “sanctity”(holy state/state of being sacred) minus(banishes) “ct”(abbrev. for “court”).
9. Quick to cover up Royal Institution’s copyright infringement (6)
PIRACY : PACY(quick/able to move fast) containing(to cover) reversal of(up, in a down clue) RI(abbrev. for “Royal Institution”).
14. Current route exposed bad roundabout (10)
CIRCUITOUS : CIRCUIT(the route/network of conducting material that an electrical current takes) + 1st and last letters deleted from(exposed) “lousy”(bad/of poor quality).
17. Start blazing row to curb enthusiasm (3,4,2)
SET FIRE TO : [SET TO](a row/an argument) containing(to curb) FIRE(enthusiasm/zeal).
18. Women-only screening of Cube and Up (8)
HEIGHTEN : HEN(an adjective indicating that, say, an event, is open to women only) containing(screening) EIGHT(cube of the number, 2).
Defn: To …/to increase, in intensity or degree.
20. Model quickly gets saddle sore (7)
SITFAST : SIT(to model/pose for an artist) + FAST(quickly).
Defn: Sore on the horse’s back, not the rider’s bottom, due to the saddle rubbing on it.
21. Court accepting jurist’s conclusion is accurate (4,2)
SPOT ON : SPOON(to court/to kiss and cuddle, as in “By the light of the silvery moon, I want to spoon, to my honey…” containing(accepting) last letter of(…’s conclusion) “jurist“.
22. Partner backed up Excel files on this? (6)
LAPTOP : Reversal of(… backed up, in a down clue) PAL(one’s mate/partner) + TOP(to excel/to be better than).
Defn: …, electronic files, that is, including Excel spreadsheets.
… after all, it is a laptop.
24. Comparatively sensitive whistleblower’s upset about heartless intimidation (5)
FINER : Reversal of(…’s upset, in a down clue) REF(short “referee”, a match umpire who uses a whistle to signal) containing(about) “intimidation” minus all its inner letters(heartless …).
26. Supporting part gets Oscar for Child’s Play (4)
LEGO : LEG(a supporting part, of a body, say) plus(gets) O(letter represented by “Oscar” in the phonetic alphabet).
A lot of the solutions sound like they may be movies. Certainly, COCOON, ALIEN & SUSPICION. The LEGO movie and there must be several HAMLET movies. I leave it to the more knowledgeable to either expand on this or discard it as twaddle.
Liked the construction for SPECTRE. Just couldn’t see CIRCUITOUS even with all the crossers and used a word fit cheat.
Thanks to Basilisk and scchua.
Good spot, Hovis: there’s also GRAVITY, ATONEMENT and PARASITE (the Korean film that was famously the first non-English language film to win the Best Picture Oscar).
…and of course SPECTRE is a James Bond film.
Yes Hovis! There’s The Last Tango in Paris, The Greatest Story Ever Told.
Hats off to Basilisk.
… and Wall Street.
In fact, all the across entries are films.
A wonderful crossword!
Many thanks to scchua for the excellent blog, and to everyone who has taken the time to commment.
As Sil has observed, all the across entries are films. In fact, each film won an Oscar for something or other.
This one really needed a lot of work to tease out. I wondered about a film theme but didn’t spot anything like all the thematic references. Ended up missing out on HEIGHTEN and had to “hit and hope” for TSOTSI and SITFAST, both of which were new. I spent ages trying to work it out, but worth it in the end eventually getting PARASITE.
A terrific puzzle – the best of a very good bunch today.
Thanks to Basilisk and scchua
A tricky crossword but one where I spotted the theme quite early on
Thanks to Basilisk for the entertainment and scchua for the explanations
Think I’ve seen nearly all of these films bar the LEGO movie but this was my favourite clue. Much as I enjoyed the cinematic theme, it didn’t exactly give me an edge in finishing a tough puzzle! What a strange and muted affair this year’s Oscars is likely to be.
Wistful thanks, then, to Basilisk and Sschua for a very helpful blog.
Great clue for Hamlet
Great puzzle- i intend to see Parasite -and that does include the letters for Paris to go with Tango
Thanks JC and scchua
Wasn’t sure what USP meant, and got TSOTSI from the two crossers I had in place. Missed the theme as per usual. Not surprising, only ever seen 3 of them.
Found this very hard, even with the movie theme and automated help. Too many words I didn’t know. Still I enjoyed the ones I got.
Not only were all the across answers names of films, but at least four of the down clues involved movie names. Perhaps Basilisk has spent a lot of the pandemic watching movies.
Thanks Basilisk, for dropping by. It’s a fantastic achievement with the ghost theme.
Both this one and Pick in the Graun were difficult but glad I completed both. Keep it up you two, I like such challenging puzzles.*Puck, sorry.
Thanks Basilisk and scchua
A tough, but very enjoyable, puzzle that took well over the hour to nut out. Noticed a sprinkling of movies throughout the clues themselves, but didn’t twig to some (indeed all of the across clues) to be movies as well.
Found the word play bits as in the RE in SPECTRE and the [L]OUS[Y] in CIRCUITOUS the most difficult to unravel. Other bits such as USP and answers such as SITFAST and TSOTSI which were new or very deep down in the mind’s repository, also caused delays.
Liked the clever inter-related surface with LAPTOP and the tricky misdirection with “The Observer” and “saddle sore” (where took ages to see that it was a horse’s problem and not the rider’s).