Here is the full list of all 26 Island of the Ancients achievements.
Find Wand of Power
Kill First Enemy
Find First Weapon While Hunting
Find Survivors
Kill Barbarian and Take His Armor
Kill 100 Enemies
Switch Places with Koyukon the Bear
Kill T-Rex and Take the Egg
Find 3 Animal Companions
Go Hunting with a Survivor Companion
Switch Places With Partner
Kill an Enemy While Cloaked
Follow the Mermaid
Defeat the Lady in Red
Rescue Your Kids
Find All Animal Companions
Find All Weapons
Kill 1000 Enemies
Kill a Cloaked Enemy
Find All Items, Companions & Survivors
Escape the Alien Base
Win the Final Battle
Kill a Spinosaurus
Kill Druid Boss and Take Her Armor
Finish Game with 3 Deaths or Less
Finish Game Without Dying