This really is a multiplayer game, where playing against fallible human opponents results in a much more interesting experience. The single player mode feels included out of habit rather than any driving need. The rather small number of maps is also a shame, even though the modding community will no doubt address that problem soon enough.
As such, the rather clumsily titled Multiwinia sometimes feels more like a long lost multiplayer mode for the original Darwinia than a standalone game in its own right. This is, after all, how the project began (and how it will eventually appear on XBLA when the two games are merged into Darwinia+) but at budget price this is a minor quibble rather than a serious complaint.