They Are Billions is the video game equivalent of spending time assembling some sort of mechanical thing - a rocking chair, let's say, with various interlocking parts. And then, as you step back to view your good work, the cat springs up onto it and, eyes locked with yours, lets loose a magnificent, four-tiered modernist turd right into the middle of the seat.
With this glorious, punishing early-access title, developers Numantian Games seem to have done that rare thing where you stick together various aspects of existing games, and you go: "There. A game." And it somehow works. They Are Billions is about 30% real-time strategy (but pausable, thank frick), 30% tower defence, 20% staring at your buildings going "ooh, steampunk, me likey", and 20% staring at the defeat screen after everything you've built has been overrun by thousands of drooling zombies. Presumably they'd also spent their time gazing at your buildings and going "ooh, steampunk, me likey".
Strangely, the bulk of the game is meant to be the campaign, which Numantian are still working on, and the wave-based tower defence mode was more of a proof of concept. But there's something really special about They Are Billions. The way it keeps you scared, even during moments of relative peace. The way it leaves you to slowly explore outwards from the centre of the map and see just how many thousands of zombies are waiting for you, just beyond the borders of your city. The way it generates such fantastic, characterful anecdotes of Achillean heroism and Sisyphean despair. It all adds up to a pretty delicious experience that keeps you coming back even after it defeats you time and time again, and, more importantly, even after you finally complete it, too.
Watch out for the Harpies though. Those lightning-quick, wall-climbing redheads are terrifying enough that you might not need the cat to soil your chair.