The Plays of the Bard XII by Salamanca

Salamanca's Shakespeare series arrives at Titus Andronicus. Unlike the last few entries in the series this seemed a bit pedestrian, given the apparently rich potential for thematic treatment in this most graphic of the plays. Two levels of message led the solver to a pie-shaped area in the final grid containing the names Chiron and Demetrius, the two sons of Tamora whom she was forced to eat in the final scene of the play (Alarbus, a third son, was disposed of much earlier in the play). Selecting the correct letters from the extra words in the clues (first letter if the first word, second letter if second word etc) led to the message "Read the fourth letter of each clue in order". Following this instruction led to the message "Straightly outline the pie of Tamora's sons". Since two of the straight lines must be diagonal to outline the pie shape, their exact positions was a little ambiguous, but the published solution apparently acknowledges this.

The solver was assisted by some fairly easy long answers (5 and 7 down for instance) to make early progress. The positioning of the thematic extra words did seem in some cases to lead to unnecessarily prolix clues (23A and 32, for instance) but the clueing was otherwise precise and fair.

Extra words are shown in square brackets.

Across
3 First part of play by new [scholar] in first outing having three extended parts (10)
TRIACTINAL (ACT I + N(ew) inside TRIAL)
11 A native woman holds Monet ruined [picture] done over a short time (9)
MOMENTARY (Jumble MONET inside MARY)
12 A foreign soldier, one [casually] takes his country's coin king's taken out (5)
ANZAC (AN + ZACK (Australian coin) minus K)
13 It catches everything in its path -- terrible danger to [weaverbirds] (7)
DRAGNET (Jumble DANGER + T (= TO))
15 Radio set's broken? [What] uncoordinated ass dropped valve? (6)
TRIODE (Jumble RADIO SETS minus ASS)
16 [Hinged] item which clasps attache cases (4)
TACH (Hidden inside atTACHe)
17 Our [hero], kind, properly English -- Wellington? (8, two words)
IRON DUKE (Jumble OUR KIND + E)
19 What [afara] trees in swamp use for breathing? Very good when end's promoted (4)
KNEE (KEEN with N moved forward)
20 [Outlandish] gift given at New Year by Stephen French, right for one? (7)
ETRENNE (ETIENNE with R(ight) replacing I)
Etienne is presumably the French form of Stephen, not confirmed in Chambers.
23 Wire creatures that are invading insects; our [neighbourhood] digs are affected (7)
GORDIUS (Anag. OUR DIGS)
25 [Rococo] temple found in Greek island with no cross (4)
NAOS (NAXOS minus X)
26 [Troutlike] fish dover sole would go well with (8, two words)
LEMON DAB (Dover sole is a somewhat similar fish...???)
28 That [there] odd cowpat (4)
TATH (Anag. THAT)
30 Cell-makers (of a kind) producing [primal] urges around end of organ (6)
GONADS (Last letter of ORGAN inside GOADS)
31 I'll instigate [dreadful] reactions in hopeless cretin (7)
INCITER (I' (IN) + jumble CRETIN)
32 You need extraordinary nerve for [executing] such plots (5)
ERVEN (Anag. NERVE)
33 Made long speech -- was boring without fine [contrast] (9)
PERORATED (PERFORATED minus F(ine))
34 Milton used this in his epic lady and gent's work about [indisputable] right (10, two words)
GRAND STYLE (R(ight) inside jumble LADY GENTS)

Down
1 [Rich] fine and witty old fop (5)
SMART (Three meanings)
2 In West Indian headdress [fellow's] partly drunk tinnie in vindication (8)
JONCANOE (ON + CAN inside JOE)
4 A republican protecting a revolutionary [belief] no longer held out (7)
REACHED (A + CHE inside RED)
5 Indian metric [poetry] form made to appear wrong (12)
INCRIMINATED (Anag. INDIAN METRIC)
6 Incentive for some [repairing] rust on vehicle (6)
CARROT (CAR + ROT)
7 Major crime creating terror in [minuscule] baby (12, two words)
TRAIN ROBBERY (Anag. TERROR IN BABY)
8 Half nude, [otherwise] detailed by big runner? (5)
NANDU (i.e. N AND U)
Good clue, "detailed" leading the solver to expect something would lose its last letter.
9 West Indian fruit used in cake [classics], etc (4)
AKEE (Hidden in cAKE Etc)
Hidden answers across extra words seem to be quite common with this kind of thematic treatment, making them quite easy to spot.
10 A weapon (of wood) [really] slow male held (6)
LATHEE (HE inside LATE)
"Of wood" seemed added simply to get the word count right.
14 One [multifoliate] river plant (4)
ACER (ACE + R(iver))
18 [Ectotrophic] plant small sweet doubly-tailless ass turned up eating (8)
KNOTWEED (TWEE inside DONKEY, minus last two letters and reversed)
21 There's endless [noise], it seems, with nitrogen moving up in the intestines (7)
ENTERAL (ETERNAL with N(itrogen) moved up)
22 Bread made by [frenetically] heartless "gifted" chap (4)
NAAN (NATHAN minus middle two letters)
23 [One] swallowing in drink is using pot and brush? (6)
GLUING (IN inside GLUG)
If this analysis is correct, the clue must be read as "Swallowing in, drink...".
24 Cows have these things that help steer head off [backpackers] (6)
UDDERS (RUDDERS minus first letter)
27 A Scots mist has a [fulvid] brown colour (5)
MOCHA (MOCH + A)
29 A language of rustic [Western] Italy (5)
HINDI (HIND + I(taly))
30 [Russian] knot gave characteristic sound when soaring (4)
GNAR (RANG rev.)