We are currently adding another game-mechanic to the mix: technological achievements, which can be compared to Technologies of Sid Meier’s Civilization-series; a tech achievement is a cultural groundwork for certain types of new buildings you might want to add to your settlement. It also acts as modifier for the settlement’s stats like taxes, community, waste, enlightenment and so on. We originally tried to avoid to have a tech-tree, but it turned out that such mechanic just helps to keep track of the general development status of a settlement; it also empowers players to choose into which direction they want to take their village when competing against other players.
Coobico does not try to compete with Civ though; we have thinned down our tech achievements to the following short list:

Mixed Farming: One of the basic achievements which enables farm-buildings.
Brewing: allows for building a tavern and raises the settlement’s food-supply.
Mining & Quarrying: enables mines, but also raises the level of pollution.
Coinage: raises both the amount of tax and crime and is necessary to build a merchant.

Militia: required for building a guard-tower, and reduces the crime-rate a bit.
Craft: enables workshops and raises the level of enlightenment.
Chemistry & Pharmacy: necessary for building a healer.
Middle Class: required for both building a healer and a scholar. Middle class will both raise a village’s tax- and pollution-rate.

These two techs are negative achievements which lead to the construction of hazard-spots; Rites is required for building graveyards. Organized crime enables building a den of thieves.
All of the above achievements can be obtained by either spending gold or accomplishing quests which grant tech achievement points.
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