Ok, so this Devlog here will tell you guys a bit about them blocks.
DIRT
Dirt is the most basic block. It's only purpose os to be a place holder for another blocks. Costs 5 bucks, and is not affected by the Earth Golem.
WOOD
Wood is a little bit more resistant then dirt. It has no immunities. Costs 20 bucks.
STONE
Stone is pretty resistant, but has no immunities, too. Costs 35 bucks.
BRICK
Brick is as resistant as stone and is immune to explosions. Not goblin safe, though. Costs 50 bucks.
BLACK BLOCK
This one is only for artistic purposes. Same price as dirt, less resistant than dirt.
GLASS
As resistant as wood, immune to the "Spit". Costs 100 bucks.
That's pretty much it. If you have any other block ideas, please leave a comment here.
Any thoughts on including blocks made of metal, or different types of stone?
It seems like you have everything fairly well-thought-out already, but maybe you could put in a few tweaks here and there to make the construction a little more resistant to attack.