From what I can see, for the third *if statement and down you don’t have enough parentheses.
Here are the first two:
*choice
*if ((first_feature = "none") and (second_feature = "none"))
#Human
*if ((first_feature = "pointed ears") and (second_feature = "scales"))
#Dragonborn
After that, the rest of them are missing them. All but one of them has only one starting parenthesis, and you forgot to put them in the middle to separate the two variables. The ending parenthesis is also missing by one. So, if I got my lines right, it should look like the below:
*if ((first_feature = "horns") and (second_feature = "claws"))
#Demon
*if ((first_feature = "claws") and (second_feature = "tail"))
#Werewolf
*if ((first_feature = "antlers") and (second_feature = "feathers"))
#Harpy
*if ((first_feature = "feathers") and (second_feature = "tail"))
#Mermaid
*if ((first_feature = "fangs") and (second_feature = "scales"))
#Vampire
*if ((first_feature = "animal ears") and (second_feature = "tail"))
#Nymph
*if ((first_feature = "unusual skin tone") and (second_feature = "feathers"))
#Fairy
*if ((first_feature = "fur") and (second_feature = "claws"))
#Wendigo
*if ((first_feature = "pointed ears") and (second_feature = "feathers"))
#Elf
*if ((first_feature = "claws") and (second_feature = "unusual skin tone"))
#Orc
*if ((first_feature = "antlers") and (second_feature = "fur"))
#Wendigo
*if ((first_feature = "scales") and (second_feature = "feathers"))
#Dragonborn
*if ((first_feature = "tail") and (second_feature = "unusual skin tone"))
#Djinn