Cervi              : Worms
pocet cervu        : number of worms
rychlost           : speed (of the worms)
zrychlovat         : accelerate (the worms go faster and faster)
do kolika se hraje : winning score (how many points to win)
mazat mrtvoly      : remove dead worms (if a worm dies of hitting
                     another or a wall, it is removed from the screen)