Should only unlock extinction when you get !! sharks. Sometimes it won't allow me to revive when I watch ad even tho it makes me watch it anyway. Sharks that cost pearls are overpriced and speaking of pearls if you crash then it will just steal the money you payed to play extinction. I am most displeased with this game nowadays as I just can't seem to get ANYTHING done. Please make sure crashes happen less often and that it doesn't steal ur coins if you crash while playing extinction mode.