Best IO games of 2021

The best .io games still have a place, even if that place is taken up by mobile games that offer more premium, on-the-go experiences. But amid all that flash, tiny, browser-based minigames still deliver an intense, multiplayer rush.

The best .io games continue to be a viral phenomenon popularized by Twitch streamers and their presence in an episode of House of Cards. The “.io” extension stands for the British Indian Ocean Territory, but because Agar.io, one of the first super popular multiplayer .io games used the extension, it’s since become a popular choice, giving the name to the genre. 

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Light and accessible but capable of intense and sometimes even ruthless gameplay, the best .io games can be played even on a spotty connection and old hardware. With the sheer number .io games out there, it can be hard to figure out which ones are worth a shot, so we’ve collected a list of the best .io games that keep us coming back for more.

The best .io Games you can play right now

1. Agar.io

(Image credit: agar.io)

The great granddaddy of them all, Agar.io (opens in new tab) is an eat or be eaten game of cellular survival taking inspiration from the behavior of microbes on top of the agar medium of a petri dish, hence the name. 

Players start small, zipping around the map and eating food to gain size. Eventually, you grow large enough to engulf other player cells, resulting in a deadly cat and mouse game as you try to lure other cells into your grasp while evading larger swarms of players that can engulf you. Simple but tense gameplay made it a viral sensation, as it was even featured in an episode of House of Cards.

2. Slither.io

(Image credit: Slither.io)

Slither.io (opens in new tab) takes inspiration from the classic game of snake, as players slither around the map consuming motes of food in order to grow in size and points. Maneuvering is the name of the game here, as players are eliminated when their snake’s head collides with the body of another snake, resulting in players suddenly changing direction or coiling around in order to trap and eliminate the unwary.

3. Diep.io

(Image credit: Diep.io)

Diep.io (opens in new tab) is another classic game, this time with players controlling tanks, destroying obstacles and enemy tanks to gather points and level up their own machines. A reasonably involved upgrade system lets you outfit your tank to your liking, allowing you to build bullet-hell monstrosities, agile attackers, or powerful snipers. 

Varied game modes, from free-for-alls to team battles and more give Diep.io some good replay value and reasonable depth, while still being a pretty accessible browser game.

4. Gats.io

(Image credit: Gats.io)

Gats.io (opens in new tab) takes the military shooter top-down, as players select weapons and armor and then carefully hunt each other down in a tight maze of barriers and passages. Each weapon brings its own advantages and disadvantages, and players will have to balance out the mobility and protection tradeoffs of armor or the lack thereof. 

Fast playing and reasonably accessible, Gats.io offers free-for-all, team deathmatch, and control point domination modes, giving you some variety in gameplay.

5. Brutal.io

(Image credit: Brutal.io)

Brutal.io (opens in new tab) lives up to its name as players pulverize each other with giant spinning balls of death. Starting out with a small morningstar-like ball attached to your player, you’ll sprint around the map to gather up food, slowly growing the size of your deathball, which you can then fling at other players, using a combination of spin, planning, and more than a little dumb luck. 

If the throw doesn’t get them, then the return just might, as holding down your mouse button summons the deathball back to the player’s tail, flattening everything in its path.

6. Gartic.io

(Image credit: Gartic.io)

Tired of the kill-or-be-killed intensity of other .io games? Gartic.io (opens in new tab) is a far more laid-back affair, as players take turns in a charades style game, with one player drawing a designated word and the others having to guess what that word is. 

Gartic handles the scoring and book keeping, and language-based game rooms allow you to play in the language of your choice.

7. Warbot.io

(Image credit: Warbot.io)

Warbot.io (opens in new tab) is a bit of an outlier among other .io games in that it features 3D graphics, providing great eye candy, but also slowing down loading times, especially for those without high speed connections. 

Warbot is a top-down twin-stick style shooter, with the mouse cursor controlling your aim, while the WASD keys control your movement. Players march through the battlefield, engaging other mecha while dodging enemy fire, gathering powerups and crawling up the leaderboard.

8. Zombs.io

(Image credit: Zombs.io)

Zombs.io (opens in new tab) brings the inevitable zombie survival spin to the genre, as players slowly build up their bases, establishing defenses and walling off choke points, gathering up resources in the daytime and fending off the hordes at night. From there, it’s a battle of endurance and survival as you upgrade your towers and personal gear in order to fend off ever tougher waves of the undead.

9. Wings.io

(Image credit: Wings.io)

Wings.io (opens in new tab) takes the multiplayer mayhem to the skies, as players engage in 2D grand melees, their fighter planes rocketing all over the place, picking up powerups, weapons, and engaging in twisting dogfights as you try to line up the perfect shot while keeping your tail clear of enemy fighters. Look elsewhere for deep simulation, as this is a whirlwind furball of planes zipping around and engaging in fast-firing carnage.

10. Deeeep.io

(Image credit: Deeeep.io)

Deeep.io (opens in new tab) has you evolving into a variety of fish and animal forms as you gather food and explore the deeps and shallows of the sea. Each animal form comes with its own abilities and is optimized for different biomes, giving players a lot of variety as they slink around, hunt other deep sea beasts, and explore what the oceans have to offer. 

You can play Deeeep.io aggressively like in other PVP style .io games, or you can evade conflict and just explore and try out the capabilities of each of the forms, giving you a fair amount of stuff to play with. 

11. 2048.io

(Image credit: Gabriele Cirulli)

2048.io (opens in new tab) is a puzzle game, in the same vein as 1024, which itself is more like Threes. You move squares around a board, trying to combine like numbers to make larger ones (2 to 2, 4 to 4, and so on). It’s very simple game, but difficult to master.

Eventually, your board will be so full that you can’t make any moves. At this point, you’ll need to start over and be more strategic the next time you play. It’s an addicting game and perfect for killing time.

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