Cheats:

 Type them in whenever you need them:

 IDDQD           - Instant Death
 IDKFA           - No Weapons/Ammo
 COCKADOODLEDOO  - Turns yourself into a chicken
 ENGAGExx        - Level Warp (episode/map)
 GIMMExx         - Artifacts (a-j) (1-9)
                   A  - Ring
                   B  - Mask (Invisibility)
                   C  - Potion
                   D  - Mystic Urn (doesn't work)
                   E  - Spell Book
                   F  - Torch
                   G  - Hour Glass (Time Bomb)
                   H  - Eggs (Turn People into Chickens)
                   I  - Golden Wings
                   J  - Chaos Device
 KITTY           - Toggle Clipping
 MASSACRE        - Kills all monsters on level
 PONCE           - Full Health
 QUICKEN         - God Mode
 RAMBO           - All Weapons/Ammo
 RAVMAP          - Changes Map Mode [must be in map mode]
 SHAZAM          - Toggles Weapon Power
 SKEL            - All Skeleton Keys
 TICKER          - Display fps dots

HexCheat:

 And the offsets list of the savegame for all you hexer out there:

 60 - Health                                    -(0-200)
 64 - Armor                                     -(0-200)
 68 - Shield                                    -Numbers 01
 6C - Icon at Inventory loacation number #1     -Icons  - 01Ring
 70 - Number of inventory item #1                       - 02Mask
 74 - Icon at Inventory loacation number #2             - 03Potion
 78 - Number of inventory item #2                       - 04*** Don't
                                                          use.
 7C - Icon at Inventory loacation number #3             - 05Book
 80 - Number of inventory item #3                       - 06Torch
 84 - Icon at Inventory loacation number #4             - 07Hour Glass
 88 - Number of inventory item #4                       - 08Egg
 8C - Icon at Inventory loacation number #5             - 09Golden
                                                          Wings
 90 - Number of inventory item #5
 94 - Icon at Inventory loacation number #6     -Numbers 01-63hex
 98 - Number of inventory item #6
 9C - Icon at Inventory loacation number #7
 A0 - Number of inventory item #7
 A4 - Icon at Inventory loacation number #8
 A8 - Number of inventory item #8
 E4 - Number of Items in inventory              -Numbers 00-08
10C - Yellow Key                                -Numbers 01YES
110 - Green Key
114 - Blue Key
134 - Staff
138 - Wand
13C - Crossbow
140 - Dragon's Claw
150 - Gloves
158 - Wand Ammo                                 -Numbers 0-03E7
15C - Crossbow Ammo
160 - Dragon's Claw Ammo
174 - Wand Max Ammo
178 - Crossbow Max Ammo
17C - Dragon's Claw Max Ammo
190 - God mode and clipping                     -God02, Clipping01,
                                                 Both03
 EC - Ring Time  (Low Adress)                   -1 minute  0834hex
 ED - Ring Time  (High Address)
 F0 - Mask Time  (Low Adress)
 F1 - Mask Time  (High Address)
 F8 - Torch Time (Low Adress)
 F9 - Torch Time (High Address)
 FC - Book Time  (Low Adress)
 FD - Book Time  (High Address)
100 - Wing Time  (Low Adress)
101 - Wing Time  (High Adress)