Unlimited lives:
Load or reset the game, then execute the following BASIC command before running or restarting the program. 

POKE 15942,173

R, GET GREASE GUN, R, R, USE GUN ON CART, D, GET KEY, U, Lx10,
USE KEY ON DOOR, R, R, U, GET SPADE, D, R, USE SPADE BELOW
SPIDER, D, GET TROWEL, USE TROWEL ON UPPER MUSHROOM, R, R, GET
CUTTERS, L, L, U, Lx7, D, L, L, DROP CUTTERS ON CHAINS, L, L, GET
WIG, Rx4, U, Rx3, DROP WIG IN POT, Lx3, D, D, GET RAINCOAT, U,
U, Lx3, U, TAKE DRY ICE, D, Rx3, D, Lx4, USE DRY ICE, L, TAKE
AMULET, Rx5, U, DROP AMULET, D, R, GET GUN, L, D, KILL GHOST, R,
D, GET GOLD, U, L, U, U, Rx9, DROP GOLD IN BUCKET, GET LINING,
Lx6, DROP LINING IN POT, Lx3, D, D, Rx3, GET OIL, Lx3, U, U,
Rx13, DROP OIL ON DRAWBRIDGE, TAKE FEATHER, Lx10, DROP FEATHER
IN POT, Rx12, TAKE TROLL BREW, Lx12, DROP BREW IN POT, R, TAKE
TORCH, L, LIGHT FIRE UNDER POT, R, R, TAKE FLASK, L, L, DROP
FLASK ON POT, L, L, L, TAKE AMULET, Rx14, U, R, DESTROY
FIREBALLS, L, D, Lx11, TAKE FLASK, Rx11, U, R, DROP FLASK BY
ZAKS......Done It!!

Note: Several objects are useful in this game, but are not vital
to complete the adventure. Just for the record, these are:

CLOVE OF GARLIC - Kills bats
INSECTICIDE - Kills Spiders
BIRD SEED - Kills...er...Birds
PICKAXE - Unblocks tunnel, to get dagger
HARD HAT - Destroys falling stalactites
EMERALD - Drop on yellow statue to enter tomb

There is also the following cheat:
Pause the game and type in NOOTRAC 4571. Dizzy will disappear and
you can move around thr screens using Z and X. Press space to
make Dizzy reappear in your chosen screen.

This Solution was found at the Spectrum Game Database.