Knights and Merchants cheats and cheat codes for PC

Select any levels and get bonus items:
Click on the Storage House to open the inventory window. Then, click 
once on the following items. A red triangle will appear in the item's 
square as each is selected.

Click on Row 1/item 3/wooden boards
Click on Row 2/item 2/iron bars
Click on Row 2/item 4/wine casks
Click on Row 3/item 1/bread
Click on Row 3/item 5/cooked meat
Click on Row 4/item 1/animal hide
Click on Row 4/item 5/plate mail
Click on Row 5/item 1/axes
Click on Row 5/item 2/swords
Click on Row 5/item 3/lances
Click on Row 5/item 4/pikes
Click on Row 5/item 5/long bow

Then, click on Row 6/item 1/crossbow to add 10 of each item to 
your inventory.

or 

To complete the current level click on Row 6/item 2/horses.