For 100% runs, you don't need to get that last "hidden" upgrade (I don't even think it's possible), and you don't need to go over the max food count (the reset).

As long as you have all the upgradable stuff, 50 minions, and maxed out food-gathering-locations, you are considered done, and the last thing you need is to buy the last purchasable thing, the upgrade that ends the game.