You are the first person, that I am aware of, that has defeated the game!
Instead of set difficulty levels, the item system serves as a "soft" difficulty level. So the more items you use, the easier the game will be.
The big challenge is to defeat the game without using any items. I will probably add an achievement for this later on in the STEAM version.
-Too much income from housing:
This is tricky. I don't want to add in some kind of artificial limit to housing income. This will add limitations to what the player builds. I will consider.