Just edit your save file. It's super easy in this game.
IMPORTANT: Back up your save file before messing around with it. Just rename it to "old save" or something.
Just go to "C:\Users\YourUserAccountName\AppData\Local\Valdis_Story_AC" and open the vvvX.dat file with a text editor like notepad. You may need to specify the text editor to look for "all files" to make it appear. Be sure to save the file or the changes you make won't take.
"X" can be one of several different letters and there will probably be more than one. Shouldn't be hard to figure out which one is yours. Just look for this line: global.save_current=1.000000 or 2.000000 depending on which save slot it's in.
It should be near the top or bottom of the Player segment. Sometimes notepad reverses the list order, if the player segment is at the top, it will be near the top, if the player segment is at the bottom it will be near the bottom.
You can cut and paste the address above in the address bar of any open folder in Windows to reach it if Appdata is hidden on your system. Just be sure to change the User Account name to the one you're using on your PC.
It's pretty straightforward from there.
I was able to hack my location using "global.room_loc=" at the top of the map section.
Most of what anyone would be interested in is in the Player or items section. There you can add or subtract skill points, magic, armor, weapons, and whatever. It's pretty straightforward and not difficult to figure out. Most of what you'll want to mess with is pretty self explanatory.
Here's an item list. I figured it out by putting a different value for each item. Change the value after the "=" to the number of items you want:
global.item_64=6.000000 Masters Scroll [You can't have more than 6.]
global.item_69=201.000000 Sacred Resin
global.item_67=203.000000 Pretty Flowers
global.item_62=208.000000 Spirit Potion
global.item_61=209.000000 Life Potion
global.item_59=211.000000 Mana Charm
global.item_58=212.000000 Health Charm
global.item_55=215.000000 Book of Old Gods [Having more than 5 of these will cause a freeze if you talk to the lore guy in the library more than 5 times.]
global.item_48=222.000000 Jet Black Feather
global.item_47=223.000000 Fine Blade
global.item_44=226.000000 Magician's Cape
global.item_43=227.000000 Black Heart Stone
global.item_42=228.000000 Gem of Purity
global.item_41=229.000000 Grand Agate
global.item_40=230.000000 Grey Metal Greaves
global.item_39=231.000000 Spell Lantern
global.item_38=232.000000 Grey Metal Plate
global.item_37=233.000000 ancient Coin
global.item_36=234.000000 Warrior's Plate
global.item_35=235.000000 Devil's Onyx
global.item_34=236.000000 Saint's Opal
global.item_33=237.000000 Large Emerald
global.item_32=238.000000 Grey Metal Helm
global.item_31=239.000000 Broken Doll
global.item_30=240.000000 Strange Glasses
global.item_29=241.000000 Goibniu Warrior Markings
global.item_28=242.000000 Rogue's Cowel
global.item_27=243.000000 Demon Ruby
global.item_26=244.000000 Angel Saphire
global.item_25=245.000000 Polished Stone
global.item_24=246.000000 Mark of Valdis
global.item_23=247.000000 Snow White Mane
global.item_22=248.000000 Arch Feral Spirit
global.item_21=249.000000 Greater Feral Spirit
global.item_20=250.000000 Lesser Feral Spirit
global.item_19=251.000000 Spirit Crystal
global.item_18=252.000000 Spirit Stone
global.item_17=253.000000 Spirit Shard
global.item_16=254.000000 Phantom Spirit
global.item_15=255.000000 Grey Metal Gloves
global.item_14=256.000000 Arch Angel Spirit
global.item_13=257.000000 Greater Angel Spirit
global.item_12=258.000000 Lesser Angel Spirit
global.item_11=259.000000 Silken Cloth
global.item_10=260.000000 Soft Cloth
global.item_9=261.000000 Rough Cloth
global.item_8=262.000000 Divine Dust
global.item_7=263.000000 Twisted Spirit
global.item_6=264.000000 Arch Demon Spirit
global.item_5=265.000000 Greater Demon Spirit
global.item_4=266.000000 Lesser Demon Spirit
Note that these items won't appear in your inventory unless you obtain at least one no matter how high you set the value. Once you grab one, the full amount plus one will appear in your inventory. Altenately you can edit all the "get" values to 1.000000 and they'll just be in your inventory immediately.
Armors and Weapons are in the Player area. A lot of values in this area are 1-3. 1 being the lowest tier, and 3 being the highest. So xxxx_x=1 is a 1st level item, and xxxx_x=3 is a 3rd level item. All upgradeable items and powers only have three levels, so higher values won't do anything.
You can also fix the Prison and the 3rd town in the Player section to bring everyone back if you missed fixing the heater. It won't persist and you still won't be able to get the core as Fred will forever have that screwdriver if you miss the opportunity, but you can use this to upgrade items using the smith there and use the other shops if you didn't manage to save the town in your playthrough.
I deliberately avoided key items like keys and such as to break progression as little as possible. If you really want them, it isn't hard to figure out where they are.
If you're not sure, just give yourself one of something. Save the file, and reload your game. Repeat until you find what you're looking for.
IMPORTANT: Use "Continue" and not "Retry" to reload your save. Retry reloads the game, but the saved changes won't be applied. Also, it's easier to edit and restart your game if you use windowed mode while editing saves. You don't have to exit the game, just go to the main menu and select continue.
Do not try to add Map Items. These are treasure chests, adding a value to these will make treasure chests disappear. You can use this to reset treasure chests if you want by changing the value from 1 to 0 again.