Fifteensquared

The puzzle didn’t pose much difficulty. For me the bottom left corner was the last to fall.

Across

1 NICETIES  - nice,ties
5 RUSTIC  - (citrus)*
10 PENAL  - pen,a,l
11 OVERDRAWN - two def. - In the online version, there is an unnecessary space betwen the last word and the question mark. It is not a matter of style as it is not followed elsewhere in the text.
12 EXTRA TIME - (I am t exert)*
13 ROGUE  - r(og<)ue - In the online edition, I think the space between ‘wrong’ and ‘un is missing.
14 NITWIT  - nit,wit
15 RATCHET  - (chatter)* - familiar anag. fodder.
18 MATINEE  - Solved from def. I am yet to see the homophone. Help!
20 AWNING  - (-y)awning
22 GLEAM  - Solved from def. I am yet to grasp the wordplay. Help!
24 PATRIARCH - (chair part)*
25 LIBELLOUS - li(”lie”),bello(-w),u/s 
26 GENES  - (sen, e.g.)< 
27 RAREST  -R(a)R,est. - Purists may frown on one = a - In India we use ‘estd’, not ‘est’, for ‘established’.
28 VERY WELL - two def.

Down

1 NEPHEW  - ne,phew
2 CONSTRICT - con,strict
3 TILT AT WINDMILLS - cryptic def., but not so cryptic
4 EGOTIST  - (eg is OTT)*
6 UNDERSTANDINGLY - cryptic def.
7 TWANG  - two def. It is an unstated instrument that must be highly strung
8 CONCERTO - c(once)r, to - Here and in 21dn an abbreviation, a small component, is a container rather than a contained. Does this happen often in crossword clues? I don’t recall but my memory is notoriously short.
9 METEOR  - (remote)* - familiar anag. fodder
16 HINDRANCE - (dancer in h.)* - ‘after accident” is an appropriate anag. signal
17 SMUGGLER - cryptic def. - I am not carried away by this clue.
19 EMPLOY  - em,ploy - Do we come across en, the other measure in printing, as often as em?
20 ARTISTE  - (a sitter)* - nice anag. signal in ‘fluffing’
21 CHISEL  - hise, anag. of ‘he is’, in cl.
23 EMBER  - (-m)ember - Thank goodness the last months are left alone.