They Are Billions offers an almost perfect gameplay loop, mixing tower-defence with city building and exploration, as you balance resource-management, defence and offense, all against your ever-impending doom at the hands of a world infested with the undead. The only downside to a game that looks and sounds great, offering a tense experience in a compelling setting, is a campaign that doesn’t fully make-use of the gameplay loop perfected by Numantian Games, leaving the campaign feeling weak, compared to the survival mode, which is the real draw.
Source: N4G PC They Are Billions Review – Surviving the Land of the Dead [Wccftech]