No 13001, Thursday 30 Jul 2020, Afterdark

Solution to 29A has been deliberately left unsolved and is to be answered only by a non-regular/novice commenter, with proper annotation. Those who have answered earlier in the week, please give others a chance.

ACROSS
1   Clearly defined like the squares here (5-3-5) BLACK-AND-WHITE Definition by example
10 Famous tennis player retires having pain, against Russian leader (9) GORBACHEV {BORG<=}{ACHE}{V} An error in the reversal
11 The pair buys egg from stall... (5) BOOTH {BO{O}TH}
12 ...or something egg shaped free on order (5) OVOID {VOID}<=>{O}
13 Assailant ripped apart by dogs (9) ALSATIANS*

14 Your old listener coming to the front is rude (6) EARTHY {THY}<=>{EAR}
16 Navy boarding American vessels... (4) URNS {U{RN}S}
19 ... in place of sublieutinant held in confinement (4) LIEU [T]
20 A maths problem? No it’s another problem (6) ASTHMA {A}{MATHS*}*
25 State has victory collecting small coins issued (9) WISCONSIN {WIN} over {S}{COINS*}
26 The 8th letter’s second page’s long (5) AITCH {pAge}{ITCH}
27 As per sources, Diana's uncle, Charles’ aunt Lizzie could be related to duke (5) DUCAL Acrostic
28 A film on how Titanic crashed; it’s shot with Navy’s involvement (9) CHINATOWN {HOW+TitANIC}*{N}
29 Bookings regarding supplies without significance (13) ?E?I?T?A?I?N? (Addendum - REGISTRATIONS {RE}{GIST}{RATIONS} - See comments)

DOWN
2   Wild pig, fat all around seen at port side (8) LARBOARD {LAR{BOAR}D}
3   Leafy vegetable, cold and raw (5) CHARD {C}{HARD}

4   One used butter at retreat, perhaps (6) ASHRAM {A}{SH}{RAM}
5   Visa issued to enter District of Columbia; prepared for tennis tournament (5,3) DAVIS CUP {D{VISA*}C}{UP}

6   Worker in costumes of natives, say (9) HABITANTS {HABIT{ANT}S}
7   After the onset of throat infection, sign of multiplication between neck and abdomen (6) THORAX {tHROAT}*{X}
8   Take no notice of Italian gentleman, he is off his head (6) IGNORE sIGNORE
9   Part with remark right away (5) PHASE PHrASE
15 Head office’s initial public offering is to collect money to distribute oil to common people (3,6) HOI POLLOI {HO}{IPO}{L}{OIL*}
17 Easygoing person or aggressive? Hard to say initially. Maybe a lion (8) PUSSYCAT {PUS(-s+h)HY}{CAT}
18 Say, Pondicherry district in demonstration, to start non-cooperation against closure (8) SHUTDOWN {SH{UT}{D}OWN} (Correction - {SH{UT}{D}OW}{No...n} - See comments)
21 Bach in Germany? Somewhat painful... (6) ACHING [T]
22 ... maybe it is Ludwig, Goransson that is (5) SWEDE [CD]
23 South Korean rapper at church to find energy and soul (6) PSYCHE {PSY}{CH}{E}
24 Soldier seen in a university at Chennai has chest pain (6) ANGINA {AN{GI}NA}
26 Summers are bad, animals can infringe at sources (5) ABACI Acrostic

Reference List
Against = V, Egg = O, Order = O, Navy = RN(Royal Navy), Small = S, Cold = C, One = A, Used = SH(Second Hand), Right = R, Money = L, Hard = H, District = D, Church = CH, Energy = E