As the character progresses through the game, experience points are earned that are used to achieve levels of accomplishment. Upon achieving a new level, the player receives a set of skill points that can be assigned to improve any of the Skill percentages. For instance, increasing the lock pick skill grants the player the ability to pick harder locks to unlock doors and supply crates. A Perk is granted at each level, which offers advantages of varying quality and form. Many Perks have a set of prerequisites that must be satisfied, and new Perks are unlocked every two levels.
An important statistic tracked in the game is karma. Each character has an aggregate amount of karma that can be affected by the decisions and actions made in the game. Positive karmic actions include freeing captives and helping others. Negative karmic actions include killing good characters and stealing. Beyond acting as flavor for the game's events, karma can have tangible effects to the player, primarily affecting the game's ending. Other effects include altered dialogue with non-player characters (NPCs), or unique reactions from other characters. Actions vary in the level of karma change they cause; thus, pickpocketing produces less negative karma than the killing of a good character. However, the player's relationships with the game's factions are distinct, so any two groups or settlements may view the player in contrasting ways, depending on the player's conduct. Some Perks require specific karma levels.
Health and weapons
Health is separated into two types: general and limb. General health is the primary damage bar, and the player will die if it is depleted. Limb health is specific to each portion of the body, namely the arms, legs, head, and torso. Non-human enemies will sometimes have additional appendages. When a limb's health bar is depleted, that limb is rendered "crippled" and induces a negative status effect, such as blurred vision from a crippled head or reduced movement speed from a crippled leg. Health is diminished when damage is taken from being attacked, falling from great distances, and/or accidental self injury. General health can be replenished by sleeping, using medical equipment (stimpaks), eating food, or drinking water. Limbs can be healed directly by injecting them with stimpaks, by sleeping, or by being healed by a doctor. Along with the health, there are 20 bobbleheads that can be found throughout the game that will give the player bonuses to attributes and skills. Each bobblehead is an iconic Vault-Tec Boy figurine with a different pose. Three of them have to be found in different time periods in the gameplay; otherwise they will be lost.
There are secondary health factors that can affect performance. Chief among these is radiation poisoning: most food is irradiated to a small degree, and parts of the world have varying levels of background radiation. As the player is exposed to radiation, it builds up, causing negative effects and eventually death if left untreated. Radiation sickness must be healed by special medicine named Rad Away or by visiting one of the Wasteland's doctors. Radiation…