Objective is to try and build up your church before the eclipse. The first size upgrade is unlikely to be unlocked on the first cycle without both good optimization and luck, but yea the first big major milestone goal is to get the debt paid off and small church unlocked.
More followers, more money, more upgrades.
Some things had to be cut from the game due to scope, but would like to add a bit of story and more prestige elements in the future.