It has also received some criticism however, with some players recommending that it is only suitable for strategy enthusiasts. With an 87% review score on PC Gamer, CK2 has been received well by fans, with some highlights of the game including its host of campaign missions and impressive AI mechanics. Run on Paradox Development Studio, CK2 is available on Microsoft Windows, OS X and Linux. The game was developed by Paradox Development Studio which is a Swedish Game Developer also known for the creation of games such as Stellaris and Hearts of Iron. Once players have selected a leader, they must work alongside them to ensure the successful smooth running of the land, which becomes the players full responsibility when they die. Crusader Kings II (CK2) is the second in the Crusader series and sets itself as a strategy game with RPG features, in which players set out to find a leader within the Medieval world of the 8th Century.