What is an .io game?
The name is an accident of domain pricing that became a genre label. The genre itself is one of the internet's best ideas: instant, massively shared, ruthlessly simple.
The accidental name
'.io' is the internet country code for the British Indian Ocean Territory — short, available, and cheap when developers wanted snappy domains. Agar.io took it mainstream in 2015; Slither.io cemented it in 2016. The suffix stopped meaning a place and started meaning a promise: click the link and you're playing a shared arena with strangers in seconds — no install, no account, no tutorial you can't skip.
The three commandments of the genre
One rule you learn in ten seconds (eat to grow, don't hit what kills you). Everyone in one shared space, so the difficulty is other people, not scripted levels. And runs that end — permadeath per run keeps stakes real and sessions snackable. Every successful .io game keeps all three; most failed ones broke one, usually by adding complexity the first ten seconds can't teach.
What separates good from forgettable now
A decade in, the checklist has matured: fair collision handling (who judges a hit — a server, or the luckiest client?), honest population (are those players or unlabeled bots?), monetization that stays out of the arena, and performance that holds up exactly when the screen gets crowded. The worm branch of the family is where those questions bite hardest, because bodies on screen scale with every player's success.
Where Wormifi sits
Wormifi is our worm-branch entry, built on the three commandments plus one of our own: nothing appears from nowhere. The devlog documents the whole build in public.