I’m a computer game fan, naturally, but I’m also picky about which games I like to play. I enjoy arcade games and first person shooters. I like quick action. And I prefer something that I can stop playing after a few minutes when I get bored or when work calls.

Recently, I discovered an online game called Slitherio.

Slitherio is an app, though I’ve never played it as such. Instead, when I wish to spend two or three minutes diverting my attention from work, I visit slither.io on my computer and waste time with the game.

It’s fun!

In Slitherio, you become a snake, though I prefer to think of my player as a worm. The object is to eat, which I know how to do really well. You consume various glowing dots on the screen. The more dots you eat, the longer and larger your worm becomes.

If you run into another worm, you die. Your body dematerializes into many glowing blobs, which other worms consume and grow larger, as illustrated in Figure 1.

Figure 1. Slitherio in action.

The challenge in the game is navigating your worm. You use the mouse to set the worm’s direction, but that can be problematic. When you want to speed up, you press the Spacebar or the mouse button, but you also have a tendency to move the mouse quickly. The effect is that you lose control and, always, potentially run into another worm and die.

I’ve played this game for a little as 10 seconds but as long as several minutes. My high score is about 36,000. I could have gotten higher, but I had to stop playing to attend to business.

The Slither.io website logs the top 10 scores for worms currently playing. The high score for the day is also shown, and it’s often in the hundreds of thousands. That’s a big worm.

The game has many elements that work for it: It’s quick to learn, but not easy to master. It’s fun to play, but doesn’t consume a great amount of time. If you’re good, you get rewarded. That’s probably why I enjoy it so much.

So why is it free online?

Easy answer: When you get something without paying for it, it’s you who is being sold. In this case, Slitherio lets you upgrade to a custom worm if you surrender your Facebook, Gmail, or Twitter account. I won’t do that, so I play with a plain worm. I’m good with that choice.