The walkthrough takes only 125 moves, which I think may be optimal.
However, a further point is that shooting the zombie may not work the first time - you can try up to
three times, after which it kills you, so in practice a minimum-move solution could take up to 127
moves.
DROP PAPER
INSERT COIN
EXAMINE SEAT
GET KEY
N
EXAMINE TOILET
GET JACKET
EXAMINE JACKET
EXAMINE JACKET
DROP JACKET
GET GUN
GET BULLETS
LOAD GUN
GO GRID
LIGHT TORCH
N
W
EXAMINE TRAP
GET CHEESE
W
S
DROP KEY
S
U
W
SAY 46
E
N
SAY 1953
S
D
W
W
S
S
GET AQUALUNG
W
WEAR AQUALUNG
GO AIRLOCK
SWIM
W
D
N
EXAMINE JUNK
EXAMINE JUNK
GET LAMP
RUB LAMP
D
DROP GUN
DROP CHEESE
U
U
D
GET BEAM
RUB LAMP
DROP BEAM
RUB LAMP
W
W
S
S
W
GO AIRLOCK
SWIM
W
D
RUB LAMP
GET BEAM
RUB LAMP
FIX TRAPDOOR
N
GET CROWBAR
RUB LAMP
D
DROP AQUALUNG
GET CHEESE
U
GET KEY
D
WAIT
DROP CHEESE
GET ROPE
TIE ROPE
GET CHEESE
GO ROPE
DROP CROWBAR
GO TUNNEL
GIVE CHEESE
EXAMINE ALTAR
GET TALISMAN
U
N
GO DOOR
EXAMINE JEWELLRY
DROP MATCHES
GET CASKET
OPEN CASKET
DROP CASKET
DROP KEY
GET TANNA
GET MATCHES
RUB LAMP
D
DROP LAMP
MOVE FAWKES
GET BARREL
GET GUN
WAIT
GO ROPE
E
FIRE GUN
GO DOOR
LIGHT MATCH
LIGHT FUSE
DROP BARREL
W
W
GET CROWBAR
E
GO DOOR
GO PASSAGE
OPEN SARCOPHAGUS
WEAR TALISMAN
GIVE LEAVES
WEAR MASK
