You win if you played all your tiles on the table. On your turn you can place a number tile on the table in order to continue the numerical series.
Action tiles can change the direction or enable other special actions.
Each player has a number of tiles (7 at start). Most of them have numbers (1-99), some additional special effects, some are real special tiles. Goal is to be the first player to get rid off them.
Played tiles form a row on the table, with the numbers either descending or ascending. A player in turn usually plays one of his tiles; if he is unable to do so, he draws a new tile.
Special tiles include: Draw one or more tiles and give them to other players; end the current row and start a new one; let other players lose their next turn; change the direction of play; and some more.