Attributes and karma
Character creation occurs in steps from the character's birth to their 16th birthday. At birth, the player determines what their character will look like. As a baby, they read a child's book titled You're SPECIAL, where upon reading the player can set the character's primary attributes (Strength, Perception, Endurance, Charisma, Intelligence, Agility, and Luck). Finally, at age 16, the player takes the G.O.A.T. exam to determine the first three Skills they wish to focus on (dedicating 15 points to each). Skills and Perks are similar to those in previous games: Skills can be gradually assigned up to 100 points and give players increasing degrees of ability; for instance, increasing the lockpick skill grants the player access to harder doors to unlock (in increments of 25). The maximum level the player can achieve in the standard game is level 20 this is increased to 30 in the downloadable Broken Steel content addition. With each level, the player can allocate more points to their skills and a new Perk can be selected, each offering advantages of varying quality and form. Additional Perks are made available every other level (i.e. levels 2, 4, 6, etc.).
Another important statistic tracked in the game is karma. Each player has a total amount of karma which can be affected by the decisions and actions made in the game. Positive karma actions include freeing captives and helping others. Negative karma actions include killing good characters and stealing. Beyond acting as flavour 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 NPCs, or unique reactions from other characters. Actions vary in extremes of karma; pickpocketing awards less negative karma than the killing of a good character, for example. 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.
Health and weapons
The player's health is separated into two types: general health and limb health. 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 (a crippled head causes blurred vision, crippled legs slow movement, etc.). Health is diminished when damage is taken from being shot, falling from great distances, and/or accidental self injury (stepping on a mine, for example). General health can be replenished by sleeping, using medical equipment (stimpacks), eating food, or drinking water. Limbs can only be directly healed by stimpacks, though as long as they aren't crippled they will be healed with the general health bar.
There are also secondary health factors which can affect performance. Being set in a post-apocalyptic nuclear wasteland, radiation poisoning will set in if the player stays in an irradiated area for too long. Radiation sickness must be healed by special pills or doctors. The player can also become addicted to drugs and alcohol, and then go through withdrawal symptoms if denied those substances. Both afflictions can blur the player's vision for a few seconds and have a negative effect on SPECIAL attributes until the problem is corrected.
Another game mechanic is item degradation. The more weapons and armor are used or damaged in combat, the less effective they become. Firearms do less damage and may jam during reloading, and apparel becomes gradually less protective. This will eventually result in the item breaking altogether. Items can be repaired for a price from special vendors, or if the player has two of the same item, one of the two can be salvaged to repair the other. The Repair skill must be at a certain level to repair an item beyond a certain level of degradation.
Players also have the option to create their own weaponry using various scavenged items found in the wasteland. These items can only be created at workbenches, and only if the player possesses the necessary schematics or the necessary perk. These weapons include melee, ranged, and explosive weapons, and in most cases possess significant advantages over other weapons of their type (the two explosives, for example, do far more damage than ordinary grenades or mines). Each schematic has three to four copies to be found. Each copy, up to a maximum of three, improves the condition (or number) of items produced at the workbench. A higher repair skill will also result in a better starting condition for the related weapon. Weapon schematics can be found in lying in certain locations, bought from vendors, or received as quest rewards.
V.A.T.S.
The Vault-Tec Assisted Targeting System, or V.A.T.S., plays an important part in combat. While using V.A.T.S., real-time combat is paused, and action is played out from varying camera angles in a computer graphics version of "bullet time", creating a combat system that the Bethesda developers have described as a hybrid between turn-based and real-time combat. Various actions cost action points, limiting the actions of each combatant during a turn, and both the player and enemies can target specific body areas for attacks to inflict specific injuries; headshots can be used for quick kills or blinding, legs can be targeted to slow enemies' movements, opponents can be disarmed by shooting at their weapons, and players can drive certain enemies into a berserker rage by shooting out things like antennae on various overgrown insects and combat inhibitors on armored robots. Action points can be significantly increased in a number of ways.
Companions
The player can have a maximum party of three, consisting of their character, a dog named Dogmeat, and a single non-player character. Dogmeat can be killed during the game if the player misuses him or places him in a severely dangerous situation and he cannot be replaced (this was changed with the introduction of Broken Steel: the level 22 "Puppies!" perk allows the player to gain a "Dogmeat's puppy" follower if Dogmeat dies); it is possible to not encounter Dogmeat at all depending on how the game is played. One other NPC can travel with the player at any time, and in order to get another NPC to travel, the first one must be dismissed (either voluntarily by the player or as a consequence of other events) or die in combat.
Enemies
There is a multitude of enemies that the player may encounter. There is a variety of mutated and dangerous creatures scattered across the Wasteland, including Deathclaws (large, mutant reptiles), Radscorpions (giant irradiated scorpions), mirelurks (a man-sized, bipedal crab), dogs, mad brahmin (two-headed cows), mole rats, yao guai (mutated bears), and large, yellow-green Super Mutants. The player may also encounter hostile humans, including raiders, mercenaries, Talon Company Mercs, slavers, other Vault survivors, and some people driven to madness. Some areas contain feral ghouls, ghouls who have lost their humanity. A ghoul is a human who has been transformed by "an ungodly amount of radiation". Ghouls can live to be a century or more old, some having survived from before the war 200 years ago. There are also a various number of robots with different combat armament and weaponry. Sentry bots, military robots (i.e. Mister Gutsy), and Robobrains are a few robotic adversaries (or sometimes allies) the player may encounter.
