A tech demo was released on February 16, 2008, showing the inventory system and how items and environmental objects can be manipulated, as well as how items may be used together. For example, double-sided adhesive tape can be used to attach a glow stick to a wall, creating a source of light. Another example is the player using a knife to puncture a blood pack, then throwing the blood pack creating a blood trail to lure enemies from one spot to another. A second tech demo was released on February 26, 2008, showing the realistic use of fire with various objects in the game.