In the first and second games there are items (known as presents) that the player can give to other characters. A number of these presents are references to other games or media.

One example is the rations from the first game. The description says "...and certain snakes that enjoy hide-and-seek are just crazy about it." This is a reference to the Metal Gear Solid series, where the main character is usually called Snake and uses stealth to infiltrate bases. Rations are also a healing item in the series.