In Drillin.io you control a snake with an unusually large head, Maybe it's a cobra? Who knows. In any case, you are the strongest in your head area and the weakest closer to your tail. The goal is to eat your opponents and become the biggest of them all.
The bigger the snake, the stronger it is, but you can try to creep up on your larger opponents and attack their weak spot.
If you like simple IO games, Drillin.io is a good choice.