10/4/2004: You can assign damage to multiple targets and are not forced to assign the same amount of damage to each target.
10/4/2004: You can't do fractional points of damage.
10/1/2008: The number of targets must be at least 1 and at most 4. You divide the damage as you play Pyrokinesis, not as it resolves. Each target must be assigned at least 1 damage.