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.

They Are Billions is a game based on just a single trick that’s up its undead sleeve. But it’s a hell of a trick, one that’ll keep you ensnared in its tangled web of survival for dozens and dozens of hours as the undead march upon your best base-building efforts.

They Are Billions is an interesting mashup of classic RTS, tower defense, and survival that successfully conjures up that “one more game” feel, assuming you can persevere through countless defeats.

Establishing and expanding a colony while defending against increasingly difficult hordes of infected makes for a very engrossing experience in They Are Billions, though some questionable design choices make shambling through the lengthy Singleplayer campaign a bit of a slog at times.

They Are Billions is an atmospheric mix of strategy and Tower Defense game. It isn’t without some hiccups, especially in the story mode, but this is such a great and different experience for RTS fans that you should check it out.

The mixture of base building, expansion and defense works well - especially in survival mode. The campaign is a big disappointment, though.

After starting the game, we soon felt disillusioned. The structure of the missions nevery changes and there isn‘t really a story to the campaign. The are Billions shines the most when playing outside the boundaries of the campaign, especially when playing on high difficulty.