I would love to build a zoo with all the possible animals in it. With a DLC you could always add an area with the new animals. However, I have already noticed (from other gamers) that quickly the computer has problems and so the game gets very slow. Therefore, I would find it great that you can build multiple zoos within a savegame and can switch between the zoos. The zoos can be run in parallel, so that the profit goes into "one pot".
I don't want to invest several hours that i can't use all the animals in my zoo afterwards or that the game becomes very slow.
I don't want to invest several hours that i can't use all the animals in my zoo afterwards or that the game becomes very slow.