No 14043, Tuesday 12 Dec 2023,KrisKross

Solution to 1A 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   One always fresh and smart (6) S?R?C? (Addendum - SPRUCE [DD] - See comments)

4   Key slang for "seafood" (8) ESCARGOT {ESC}{ARGOT}

10 Doc finally overwhelmed by anger after opening cavity (9) VENTRICLE {RI{doC}LE}<=>{VENT}

11 So hot again…removing shorts, stripped completely (5) HENCE {H}ENCE Anno pending (Addendum - {HE}{ENCorE} - See comments)

12 Last-minute changes to make ATM device (7) UTENSIL {+ATM = LAST MINUTE} [CA]

13 Graceful angel is so merciful at heart (7) LISSOME [T]

14 More time to pack ten tonnes (5) EXTRA {E{X}{T}RA}

15 Routine starting to debug anomalous Y-O-Y data (3-2-3) DAY-TO-DAY {De..g}{Y-O-Y+DATA}

18 Short article about unfinished, cryptic, enigmatic painting (8) TRIPTYCH {T{CRYPTIc*}He}

20 Host KrisKross returns to make an observation to the audience (5) EMCEE {ME<=}{~ see CEE}

23 Successful company - one contracting wheat possibly (7) UNICORN {UNIt}{CORN} 

25 Unwanted, nonstop jabbers? (7) NEEDLES NEEDLESs

26 Lived in degenerate retro bar (5) DWELT {LEWD<=}{T}

27 Laurel, say, always leading comic genre (9) EVERGREEN {EVER}{GENRE*}

28 Law has reviewed evidence in handbag (8) RETICULE {R{CITE<=}ULE}

29 Commands boy to leave frontiers (6) ORDERS bORDERS

DOWN

1   Enjoyed preserved painting belonging to you and me (8) SAVOURED {SAV{OUR}ED}

2   Most foul smell, primarily in dirty tanker (7) RANKEST {RANKE{Sm..l}T*}

3   Cheat using comedian's instrument (4,5) CARD SHARP {CARDS}{HARP}

5   Untrue, stale story by subordinate to win praise that should be mine (5,2,7) STEAL MY THUNDER {STALE*}{MYTH}{UNDER}

6   Losing final seconds in a game is painful (5) ACHES {A}{CHESs}

7   A long, lively party inside boat (7) GONDOLA {A+LONG}* over {DO}

8   Not those Sunday papers (6) THESES {THESE}{S}

9   Polluted Delhi can really do without pure air? Eventually, it's unlikely to happen (1,4,3,2,4) A COLD DAY IN HELL {DELHI+CAN+reALLY+DO}*

16 Go around cycling? Agree excitedly, being very enthusiastic (9) OVEREAGER {(-r)OVE(+r)R}{AGREE*}

17 Space organization involved in action, uplifting farmers (8) PEASANTS {ST{NASA}EP}<=

19 Plan to wear torn dress (7) RAIMENT {R{AIM}ENT}

21 Old king having support for educational institution (7) COLLEGE {COL{LEG}E}

22 Star very angry about part (6) SUNDER {SUN}{RED<=}

24 Choose one ultimately classic visual (5) OPTIC {OPT}{1}{c...iC}

Reference List

Key = ESC, Tonnes = T, Bar = T, Boy = B, Sunday = S