Behind the Mask solution
by Kegler
The ten modified entries each gain an unclued ID, as each has a SECRET IDENTITY.
Across
| 1 | OFFERS (2 defs) |
| 5 | LI(MP){ID}LY |
| 11 | FLY NET (LEFT NY anag) |
| 12 | MERCI (CRIME anag) |
| 14 | F(wORM){ID}ABLE |
| 16 | ONe + TwO |
| 17 | DRY (last letters) |
| 18 | NAI + ADS (IAN rev) |
| 19 | TIMe |
| 20 | AIR SAC (A CAR IS anag) |
| 21 | M,E + SA |
| 24 | DE(COD)ER |
| 25 | PACERS (RECAPS anag) |
| 26 | COVEr |
| 27 | A + VER |
| 28 | SECRET IDENTITY |
| 30 | T + RIO |
| 31 | TIRE (2 defs) |
| 32 | OT + HERS (TO rev) |
| 36 | DE[T/f]ECTS |
| 39 | IR(E)S |
| 41 | TEMPLE (2 defs) |
| 43 | DO + N |
| 45 | F + R{ID}AY |
| 46 | RAW (WAR rev) |
| 47 | I + NTO (NOT anag) |
| 48 | INTIM{ID}ATE (hidden) |
| 49 | SHEIK ("SHAKE" hom) |
| 50 | S(N)ORER |
| 51 | GRAN + DEUR (RUDE anag) |
| 52 | EGRES + S (SERGE rev) |
|
Down
| 1 | O + FF DAY (DAFFY anag) |
| 2 | FLO(R){ID}A (FOAL anag) |
| 3 | EN MA(S)SE (SEAMEN anag) |
| 4 | REIN + A |
| 5 | LI(AIS)E |
| 6 | M(EL)DS |
| 7 | PRES{ID}ENTS (SERPENTS anag) |
| 8 | ICON (COIN anag) |
| 9 | LU(TI)ST |
| 10 | YE + OMANR + Y (NORMA anag) |
| 13 | INTER + VIE + W |
| 15 | BARC + ODE (CRAB rev) |
| 21 | MEAT (TEAM anag) |
| 22 | A + C + C{ID}ENTS |
| 23 | PRETTIFIED (FIT PER DIET anag) |
| 26 | CIRC(U)IT (CRITIC anag) |
| 28 | ST(R){ID}ING |
| 29 | ROES ("ROSE" hom) |
| 33 | HUM{ID}OR (hidden) |
| 34 | RE(LATE)S |
| 35 | IRONER (RENOIR anag) |
| 37 | T{ID}IE + R |
| 38 | SE(W)ERS |
| 40 | ERN-IE (2 defs, pun) |
| 42 | E(YIN)G |
| 44 | JOHN (2 defs) |
|