Experience (abbreviated to EXP or XP) is the simplest and most common way of keeping score in Angband and most variants, and typically determines the player's character level. Experience can be gained in many ways, although encounters with monsters almost invariably account for the vast majority of it; additional sources depend on the variant.
Importance of experience
Experience is important because it determines the character level, which in turn greatly affects the player character's hit points, mana pool, primary skills, access to spells and special powers, spell fail rates, and the power of many spell effects and saving rolls. Characters may also gain additional bonuses upon reaching a certain level.
In a few variants, experience does not determine character level, but can instead be invested to gain new skills or abilities. This approach was pioneered by Sangband; it is also used in Sil and Sil-Q, which have no character level.
In variants where character level depends on experience, each character has an individual experience factor, which multiplies the experience needed to reach a given level. The experience factor depends on the character's race and class; variant-specific attributes like personality and dragon realm may also affect it. Experience factors are usually displayed as a percentage; for example, 120% for a multiplier of 1.2. The table below holds for a wide range of variants, including FrogComposband, ToME and all versions of Vanilla Angband.
Fighting monsters is by far the most common way to gain experience. Traditionally, experience is only rewarded for a kill; but Hengband and variants derived from it give partial credit for damaging a monster without killing it. The experience that can be gained from any single monster in these variants is still limited; if the fight continues too long without the monster being killed, it eventually stops giving XP.
In Vanilla Angband, the experience gained from a kill is calculated simply by taking the XP value of the monster race, multiplying it by the native level of the monster, and dividing it by the player's character level at the time of the kill; this means that the lower the player's level, the more experience a given monster is worth. PosChengband and FrogComposband use the same core principle, but apply several modifiers to the end result: high intelligence helps the player learn faster and so gain more XP; monsters unusually fast or tough for their race give more XP; to discourage farming, monsters give less XP if too many others of the same race have been killed, and also if too many monsters with the same parent have been killed. FrogComposband also gives less XP for player summons if too many have been killed. Coffee-break mode greatly accelerates XP gain from monster kills, but further increases the farming penalties.
Experience is only awarded for kills by the player; no experience is given when a monster kills another monster, although variants with pets sometimes allow the player to gain XP for kills by pets. Killing a pet is worth no XP.
Potions of Experience exist in Angband and most variants. Historically, the experience gain from a Potion of Experience was either 10 plus half the player's previous XP, or 100,000 XP, whichever was lower; but this was changed to a flat 100,000 XP in Angband 3.1.1, allowing extremely rapid level gain for players lucky enough to find a potion early in the game. Variants forked from older versions of Angband have generally retained the original formula.
Potions of Experience are very rare; but especially in Vanilla Angband 3.1.1 and up, they are potentially game-changing if found early, and allow characters to gain significant experience without killing monsters. Lord Tom relied largely on Potions of Experience to win Angband 3.5.0 with only 4 kills.
Traditionally, some experience is awarded when a new spell is successfully cast for the first time; depending on the variant, this bonus may be significant or almost negligible. Experience is also awarded for successfully identifying a new object flavor through use-ID.
Successfully disarming a trap is usually worth 5 XP, although in Angband 4.1.0 this was changed to a nonfixed bonus dependent on the trap's depth. Unlocking a locked door is worth 1 XP in most variants and in old versions of Vanilla Angband; this was removed in Angband 3.4.0.
The player can lose experience in a number of ways, such as drinking a Potion of Lose Memories, being hit by experience-draining monster melee attacks, or being hit by an element that causes experience drain as a side-effect. Ghostly, undead or vampiric monsters are frequently experience-drainers; and nether, the element of the underworld, can drain experience in Vanilla Angband and most variants. Character levels are recalculated after experience drain, and may consequently be lost if too much experience was drained.
There is no way to fully prevent experience drain; but Hold Life gives the player a save against it, and mitigates the effect if it does happen. Elemental resistances can also help where the drain is caused by an elemental attack.
Current experience is the experience a player actively has, while maximum experience (abbreviated to Max Exp) is the experience the player would have if not drained. Lost experience can be restored with Potions of Restore Life Levels, or with spells or town services with similar effects; these set the current experience back to the maximum experience. It is also possible to simply make up the gap by gaining enough new experience; the experience gain has its usual effect on the current experience but a much smaller effect on the maximum experience (10% or 20%, depending on variant), so the current experience will eventually catch up.
Even the maximum experience can be drained by some extremely rare effects; in Vanilla Angband, the only effect to do this is the activation of the One Ring. Some variants use a max max exp for scorekeeping purposes to track the highest Max Exp attained.
The player's current experience is prominently displayed in the main screen sidebar. Depending on the variant, version and options, it can be shown in either of two formats: 1) total experience, increasing as new experience is gained; or 2) experience needed for next level, decreasing as new experience is gained until the next character level is reached; this is now the usual format, supplanting the original total experience display.
Current total experience, maximum experience and the total experience needed for the next level are all indicated on the character sheet, regardless of which format is used in the sidebar. Experience, like stats, is usually printed in light green but turns yellow when drained.
Some variants allow monsters to gain experience by either killing other monsters or by draining the experience of the player. Depending on the monster's race, they may evolve into a stronger monster after reaching a specified amount of experience. In Vanilla Angband, only the player can gain experience, and monster evolution does not occur.
How games are scored depends on the variant, but scoring often relies largely on experience; Vanilla Angband's Hall of Fame scores characters almost entirely by experience, though an additional 100 points per level is given for the highest depth reached. The oook Angband Ladder's default sorting is by highest character level and experience. Traditionally, experience is capped to 99,999,999, preventing players from reaching an arbitrarily high score.
Despite this, winning with high experience is not necessarily viewed as more impressive; on the contrary, winning the game with less experience or with a lower turncount implies the player was good enough to handle the challenge more efficiently or on a less developed character. This is reflected in competitions, where winners are most commonly sorted by lowest turncount and non-winners by experience per turn. Similarly, scoring in Sil and Sil-Q rewards low turncount but not high experience.