Which is better Primal Carnage or Primal Carnage: (Primal Carnage)

What is better Primal Carnage or Primal Carnage: Extinction

I was planning to buy Primal Carnage: Extinction, but recently there was a discount on the regular Primal Carnage and I bought it. After playing it, I saw that the game is complex, monotonous, there are flaws ... But I liked it! Now I want to know what is the difference between regular Primal Carnage and Extinction? What has changed in Extinction and is it worth buying? If you played Extinction then describe to me how it differs from the usual.