The .io genre is one rule repeated: start small, consume what is smaller than you, become the thing that consumes. It took 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 about four seconds.
What it also stuck with is a lot of baggage — lobbies, skins, sign-ups, an advert between every round. None of that is the genre. The four below are the rule without the baggage.
Drain Rush 3D — the hole.io shape
Drain Rush 3D makes you an opening in the floor. You start on crumbs and finish on the plumbing, and the whole pleasure of it is the moment something you have been circling for ten seconds finally fits. Where hole.io gives you an open city block and rival holes, this gives you one bathroom and a clock, so it is a tight three-minute run rather than an arena.
Turf Rush — the paper.io shape, in 3D
Turf Rush is the territory one: leave a trail, close the loop, own what is inside it, and know that your trail is the only thing that can kill you until you get home. Running it in 3D with the camera low behind you changes it more than it sounds — in a top-down paper.io you can see the whole board and plan a long cut, and here you cannot, so a big grab is a real gamble rather than arithmetic.
Snake Sprint — the slither.io shape
Snake Sprint is eat-and-grow with other snakes in it, so you are judging length as well as position. It has something slither.io does not: an end. Grow long enough and there is a chest to open, which turns an endless arena into a run you can actually win.
Current Swim — the same rule, underwater
Current Swim adds a current that pushes you around, so position is something you have to keep paying for rather than something you set. It is the gentlest of the four and the best one to start on if the genre is new to you.
Do these need an account or a lobby?
Neither. There is no sign-up and no waiting room — the first thirty seconds are already the game, which is the part a real .io game gets right and the part portals tend to bury. They run on a Chromebook, on a school laptop and on a phone, with nothing to install.
All four are on the .io games shelf, and if it is specifically the snake rule you came for, the snake games page is honest about there being one true snake game on it.
