The goal of the game is to survive as long as possible. You and your friends share the keyboard to control the line. The lines are constantly moving forward. The players can only adjust the direction of the line.
A player loses if his line touches a line or the border of the game. He then has to wait for the start of the next round to play again. For every player you survive you get a point.
Achtung die Kurve is played on a single screen, so make sure you have some friends around!
If your using Firefox, you need to disable the following option: In "Settings" -> "General" -> "Browsing" disable "Search for text when you start typing" as it would prevent controlling the lines.
In order to play you have to add at least two players. To do so you type in the players name in the input field on the right hand side and choose a pair of keys to control the line. Then click on the "Add Player" button and the new player is listed in the player list. The color helps you to identify your line in the game.
Once you have added two players you get the "Start Game" button, located above the list of players. Press it. A new game starts. Enjoy.