The .io genre is one rule repeated: start small, consume what is smaller than you, become the thing that consumes. It got its name from a run of games on .io domains around 2015, and the shape stuck because it works on any screen and explains itself in four seconds.
Drain Rush 3D is the hole.io-style one — you are an opening in the floor, and you start by swallowing crumbs and finish by swallowing the plumbing. Turf Rush is the paper.io-style one: you leave a trail, close the loop, and the ground inside it is yours until somebody cuts the trail before you get home. Snack Snakes is the slither.io-style one — an arena of snakes where any head that touches your body bursts into fruit, so the game is making the others run into you. Snake Sprint takes the same eat-and-grow rule onto a 3D track, where length is both your score and the reason you can no longer turn. Current Swim runs the same rule underwater with a current pushing you around.
None of these need an account and none of them hold you in a lobby. The thing a real .io game gets right is that the first thirty seconds are already the game, and that is the part we kept.
