Some worlds like World 16 have technologies. Technologies are improvements to your units military attributes. For example if you have a level one Heavy Cavalry unit (a), and level 2 Heavy cavalry (b), unit b would be better equipped for battle because the unit has been improved. You have to research the technologies in your smithy to be able to use them to your advantage.
For worlds with technologies:
For a Defensive village you should have Swords, Spears, Scouts and Heavy cavalry researched to level three.
For a Offensive village you should have Axe, Light cavalry and Rams all level three.