Well, I never looked into it, but with cheat engine, if you can find the location of items, you can also change the items you have. I suspose you could find that area by looking at inventory counts. Then look through memory to change item codes of the items. I have a list of many of the older item codes on the forum. Do a search on 'registry edit', you might find my old post.

The game inventory is now saved in a serialised format in text files in your Steam folder, same location as the map data files. You'd need to decipher the format, identify the item codes and modify an existing code to change it to a different item, or to modify the quantity, then reserialise the results and save it back to the text file. WillieSea is referring to the good old days when the data was saved in the Windows registry and much easier to edit. Let us know how it goes...

i am rather good with cheat engine, what would i need to do?

To get the arrows, you would have to be very good with 'cheat engine'. Or, what I did was take one of my old save games, where we could edit our inventory, gave myself the arrows, then updated my save game to the current version. With steam saves, I don't even know if thats possible anymore since this was way back when we had the saves in the system registry. The compass is when you map 2000 islands correctly.

how would i be able to get this? also, what compass is that and where do i get it?

I gave myself 16384 of these back when the 1.6 update happened, I'm down to a mere 15943 now...