I made some changes today.
Galleon now cost 20 instead of 35.
Sand worm now only does no wall bonus when it is fighing as stated in the description.
Undead lore bonus from units is changed, its now additive.
Crusader lost its undead lore bonus.
Scout is now +1 undead lore.
Wizard is +2 undead lore.
Ghost is +3 undead lore.
Elementals price is lowered from 1200 to 950 gold.
These upgrades are applied in all games. Units that are already trained are not changed.