The game takes place one month after the events of the first game in the two cities Limassol and Kyrenia on the island of Cyprus. The Templars have moved there and Altaïr has followed them to find out their plans and take them out if he can. The main villain is Armand Bouchart, grand master of the Templars, who is hunting the apple of Eden.
The gameplay runs similarly to the original Assassin's Creed. Altaïr has the ability to move freely through each city in a parkour style based on stealth and sneaking up on targets. Players can also choose to fight their way in or go in through the front door. Altaïr's arsenal consists of his fists for melee combat, his signature sleeve sword, and a longsword.
Bloodlines features PS3 connectivity via USB, which allows players to unlock six new weapons in Assassin's Creed II when their PSP is connected to their PS3. These can also be used in the PSP version. Additionally, any Templar coins found in Bloodlines are carried over to Assassin's Creed II , and codex pages give players a health boost.
Bloodlines was released on 20 November 2009 for the PSP.