The self-painting canvas: relinquishing control in Terraria

Terraria is one of those games that tick a lot of boxes for me. It has exploration and terraforming and crafting, and tons of options for base building and combat styles. It's got just the balance of structured and freeform gameplay I enjoy, and it hits the sweet spot between "the gameworld is your canvas" and "the gameworld is out to kill you". The thing that sticks out among all the things I love about the game, however, the thing that will always come to my mind first whenever I think of Terraria, is its "evil biomes".

Terraria's "biomes" are types of regions of the gameworld characterized by their looks and theme music, as well as the enemies, hazards, and building materials that can be found in them. The game's procedural world generation ensures that any world (save for a few quirky exceptions) will contain a mixture of biomes arranged according to certain rules. The player will initially spawn in a forest biome at the center of the map, which houses comparatively tame enemies. The world will also contain a desert biome, a jungle biome, a snow biome, and so on. And there will always be one of two "evil biomes": the purple, decay-themed Corruption or the red, gore-themed Crimson. Evil biomes will contain particularly nasty enemies and pesky hazards like deep chasms that are easy to fall (or, in most cases, be pushed) into or thorns that hurt you on contact. But most importantly: evil biomes spread.

If left unchecked, evil biomes will grow farther and farther into surrounding biomes, consuming them tile by tile. One of the most haunting moments in my life as a Terraria player was that one time I realized that the Corruption biome, while I had been busy mining and building, had eaten its way through my world, right up to my doorstep. What should have become the front yard of my budding base was now sprawling with enemies and thorns, all accompanied by that eerie music. I felt immensely powerless in that moment.

Mitigating the spread of evil biomes is possible, but there is no quick fix. Long wiki articles detail the rules of biome spread, and in countless forum threads, players debate fail-safe containment measures. A common method is to "quarantine" evil biomes by digging wide tunnels all around them, which, if done correctly, is a reliable way to stop the evil biome from spreading throughout the entire gameworld. It is also incredibly arduous. Building tunnels deep and wide enough takes time, and the evil biomes won't politely wait for the player to complete them. That means you either dig fast – or, like me, you eventually give up on containment and accept that the evil biome will sooner or later have taken over large portions of your gameworld. Once a specific point in progression has been reached, the gameworld can be "purified", ridded of the evil biomes little by little. But to get there takes time. I've never even attempted it, settled instead into an uneasy coexistence with evil.

When playing games that give me a lot of freedom to shape the gameworld to my liking, be it through terraforming or base building, I will usually a) play an incredibly slow and meticulous game, and b) want to have everything just so. That about makes me the kind of player whom Terraria's evil biome spread will stress out terribly. "Everything just so" is hard to achieve when your gameworld keeps running off to do its own thing. And that is exactly what I find so fascinating about Terraria.

Normally, games don't do this. I cannot think of a lot of games that, on the one hand, give the player vast capabilities to terraform and decorate the gameworld and at the same time allow the gameworld to radically change on its own, in ways the player probably won't be pleased with. It's like Terraria is going against some fundamental gospel of crafting games, which would require that the gameworld should be waiting for the player to leave their mark: a canvas, pristine, inert, and patient.

Terraria provides you with all the tropes that make you expect a paradigm of control: Tons of things to craft, tons of materials to craft with, all in a tile-based world that can be taken apart and reshaped at will. It's a game that hands you a shovel and makes you roll up your sleeves. And then you return from your epic haul in the underground desert and find that the grass in your yard has turned purple.

If, like in many other videogames, Terraria's world is a canvas for the player's creativity, that canvas, while providing great room for self-expression, refuses to passively wait around: it doesn't fully submit to the player as its only painter. It also happily paints itself. This aspect of Terraria makes me insanely uncomfortable, and it's fantastic! I somewhat struggle with my love for crafting games because what I find so compelling about them is at the same time the source of my growing unease with them: I enjoy games that give me the power to design the gameworld according to some creative vision. I enjoy Stardew Valley for allowing me to lay out my perfect farm. I enjoy Animal Crossing: New Horizons for giving me a whole island to terraform and decorate! And I enjoy Terraria for supplying me with a vast world made up of blocks that I can take apart and reassemble into whatever I like. I enjoy games in which the gameworld acts as my canvas – and I feel increasingly conflicted about it. Do I really want to engage in enjoyment contingent on the power fantasy of being a world's uncontested master? An attitude that, in the real world, fuels so many horrific ecological predicaments?

On the one hand: yeah, actually, because it's so satisfying. On the other hand, Terraria's biome spread system makes me excited: not only because it makes for edge-of-your-seat gameplay and amazing stories, but especially because it points to a direction that videogames could lean into more often. There are certain types of videogames that we, the players, have come to expect to grant us insane amouns of control, free of the conflicts and trade-offs of the real world. Maybe videogames could benefit from sometimes subverting that expectation. By, instead of feeding our insatiable hunger for gameworlds that bend to our every will, give us gameworlds capable of fighting back, or undergoing dramatic changes all by themselves, and thereby escaping our vision. I think that could make for incredibly interesting, innovative gameplay. Terraria, a game now well over a decade old, has shown us one way this can be done. I'm sure there are many more ways to be found, and I want to see more of them in videogames – not in spite of, but because of, how uncomfortable it makes me.