Cataclysm: Dark Days Ahead, CDDA for short, is a free and open source apocalypse-themed roguelike that is incredibly deep and a ton of fun to play. If you haven't heard of it, think of a turn-based Project Zomboid, but in addition to zombies, CDDA features alien fungi, eldritch horrors, giant skeletons, and dozens of other monsters eager to add you to the billions of victims of the apocalypse.
The core gameplay loop will be familiar to fans of Zomboid: you start with little equipment or knowledge, but as you gain experience and find or craft equipment and build a base an you can eke out a life on the fringes of the apocalypse. While the base game is ASCII, releases also includes several tilesets - I am using one of the included tilesets, Ultica.
Here I am a few moments after one of my first forays into the world of CDDA. I have spawned inside a FEMA evacuation shelter, and while checking the lockers for supplies I hear some terrible noises outside a window, indicated by the yellow icons. Stupidly, I draw back the curtains to take a look, and an undead horde smashes the windows and spills into the shelter, quickly chasing me down and ending my pitifully short life. Welcome to the apocalypse.
While the game is unforgiving, after a few tries (and some better luck with your spawn) you can become an absolute zombie terminator. On my current save I have fared considerably better. I march through the streets clad in heavy SWAT Kevlar and a Guy Fawkes mask, swinging my fire axe to cleave through hordes of zombies while occasionally popping batteries into my mp3 player (the music helps me stay calm). Exploring an eerily quiet town a week after the apocalypse I came across a swimming pool filled with webbed zombies that had evolved to live in the water along with a terrifying half-crocodile half-zombie. After spotting me through the glass walls of the pool, the horde smashed the glass and rushed across the street to show me their bathing suits. It took me two days to drag all the corpses into a pit and burn them, and I now have a delightful collection of swimwear.
The best example of the complexity of CDDA is its crafting system. There are hundreds of recipes, and navigating them all and understanding how to craft them is made simple through a powerful crafting interface. You can search through the recipes you know with a search engine that accepts wild cards and allows searching based on ingredients, proficiency required to craft, the characteristics of the crafted item, and more. I have never seen such a powerful or enjoyable crafting system, and it may be the single greatest feat of the game. I know this looks complicated (and it is) but if you spend a bit of time with it you'll recognize how well designed it is:
In addition to the more immediate physical threats of the apocalypse, your survivor is faced with battling starvation, dehydration, extreme temperatures, exhaustion, illness, addiction, and even depression. You can break your leg falling off a roof, go deaf from firing a rifle indoors, and be blinded by goo.
As time passes, the environment around you changes. Monsters evolve into more terrifying monsters. Like Project Zomboid, this is not a game with a happy ending for your character. Two weeks into the apocalypse, having chopped up most of the undead population of a small town, I was faced with a new problem: giant bugs, presumably attracted by the rotting corpses I had left in the street. Investigating a basement in one house with a flashlight I am met with a horrifying sight (and stench): a giant nest of cockroaches, mutated giant bugs, and their droppings covering the floor. You can see me on the staircase to the right.
I dash back up the stairs but am pursued by the larger bugs, one of which slashes open my leg. A pitched battle ensues, and I limp home with the resolution to leave the basement bugs in peace.
CDDA also features a bizarre cast of NPCs that try to survive the apocalypse along with you. One man I met was convinced that government corruption had something to do with the apocalypse, and implored me to find files in a nearby Federal building that would prove him right. I politely told him I would look into it. Another man asked me to find an American flag for him; his concern, presumably, was that the apocalypse had led to flagging (sorry) patriotism. One woman I met was convinced that the Cataclysm was connected with the songs she could hear emanating from animal bones. Some of these NPCs can be convinced to join you, after which they can guard you, be set to work at your base, teach you skills or perform first aid on you, and countless other options. Not all NPCs are so helpful, though, and the potential for violence is never far from your interactions with strangers.
There are also vehicles that you can build, find, hotwire, modify, and operate. And by 'vehicles' I mean everything from a canoe to a helicopter. There are giant swords and medieval armours. There are wild beagles. There are nuclear weapons. Despite having 40 or so hours in the game, I feel that I know next to nothing about it or what is possible. And that's a great feeling.