A gentle workout
Across
1 COLOSSAL huge LOSS (defeat) in COAL (fossil fuel)
5 SHARES parts HARE (animal) in SS (ship)
9 RUTHLESS having no pity (HUSTLERS)*
10 BANTAM bird (BATMAN)*
12 STAGE NAME cryptic definition
13 STILL dd
14 DONE finished ON (working) in DE[n] (study almost)
16 PROTEST object ROT (rubbish) in [mont]PE[lier] ST (street)
19 ABANDON complete lack of restraint A BAND (rock group) ON (against)
21 POEM verse POE (American writer) M[ilton]
24 CONGA dance CO (company)G[ala] in NA (not available)
25 CONSTRAIN force S[andinista] in CONTRA (Nicaraguan geurilla) IN (at home)
27 DIVOTS golf term for dislodged bits of turf
28 LIFELINE safety device LIFE (sentence) LINE (railway track)
29 GALORE lots of AL (Capone) in GORE (blood shed)
30 INTENDED fiancé IN (trendy) T (model) ENDED (finished)
Down
1 CARESS stroke S (son) in CARES (worries)
2 LETHAL deadly [nightshad]E in LT (Lithuania) HAL (prince)
3 SALVE comfort L (learner) in SAVE (avoid)
4 ASSUAGE soften AS (like) US< AGE (time)
6 HEADSTONE memorial HEADS (principal’s) (ETON)*
7 RETAINER servant RETAIN (bear in mind) ER (Queen)
8 SIMULATE copy IS< LA (the French) in MUTE (mum)
11 PEEP quick look (palindrome)
15 OLD MASTER eg Michelangelo (METAL RODS)*
17 WATCHDOG TV programme WATCH (see) DO (act) G (German)
18 CARNIVAL merrymaking (IVAN CARL)*
20 NICE kind IC (in charge) in NE (north east)
21 PENSION support for elderly PENS (writes) I (setter) ON (about)
22 VARIED miscellaneous (V AIRED)*
23 INDEED actually I (one) DEE (river) in ND (North Dakota)
26 THEME subject THE (article) M[undan]E
( )* = anagram [ ] = omit < = reverse dd = double definition
Rather easy but enjoyable. thanks jed and setter Uy