Gameplay
From D20advanced
A session of d20 Advanced resembles a small part of a story, ranging from a chapter of a book to an episode of a television program to an issue of a comic book. The GM and the players get together and tell a story by playing the game. The length of the game session can vary, from just a couple hours to several hours or more. Some adventures may be completed in a single session while others may take multiple sessions, just as some stories are told in one short book, while others span whole series. The episodic nature of the game allows you to choose when to stop playing and allows you to start up again at any time at which you and your friends agree.
Just like any other story, a d20 Advanced adventure consists of a series of interrelated scenes or encounters. Some scenes are fairly straightforward, with the characters interacting with each other and the supporting cast. In these cases the GM generally just asks the players to describe what their characters are doing and in turn describes how the other characters react and what they do. When the action starts happening, such as when the characters are staving off a disaster or fighting villains, time becomes more crucial and is broken down into rounds, each six seconds long, and the players generally have to make die rolls to see how their heroes do.
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Die Rolls
There are a number of different die rolls in d20 Advanced, although they all follow the core mechanic of a 20-sided die + modifiers vs. a Difficulty Class.
Dice Pools
Some abilities grant characters access to dice pools, which grant the player the option to try again on a failed check by rolling multiple dice at once and then taking the best result from all of those dice. After using a dice pool in this way, the player loses one die from the dice pool.
Negative Dice Pools
There are also some statuses which are meant to represent the buildup of harmful things, such as taint. In these examples, players roll their dice pools and select the lowest result. They don't lose one die from the dice pool for using it (since it's usually unwanted anyway), but they might be able to lower these problematic dice pools through other means.
Checks
To make a check, roll d20 and add any modifiers for traits (abilities, skills, or FX) relevant to the check. The higher the total, the better the outcome.
| Check = d20 + modifiers vs. Difficulty Class |
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Difficulty Class
Some checks are made against a Difficulty Class (DC). The DC is a number set by the GM which your check must meet or exceed in order for you to succeed. So for a task with a DC of 15 you must roll a check total of 15 or better to succeed. In some cases, the results of a check vary based on how much higher or lower the result is than the DC.
| TABLE 1.1: CHECK EXAMPLES | ||
| Task | Example | DC |
| Simplistic | Follow a mob in broad daylight | 0 |
| Easy | Climb a knotted rope against a wall | 5 |
| Average | Hear an approaching guard | 10 |
| Challenging | Repair an alarm clock | 15 |
| Difficult | Swim in stormy water | 20 |
| Very Difficult | Pick the lock to a house front door | 25 |
| Formidable | Leap across a 30-foot chasm | 30 |
| Heroic | Track a ninja across hard ground | 35 |
| Epic | Hack the Pentagon mainframe | 40 |
| Legendary | Locate a master spy in a metropolis | 45 |
| Mythical | Open the vault at Fort Knox | 50 |
| Impossible | Perform open-heart surgery on yourself with a pen knife in the dark | 55+ |
Opposed Checks
Some checks are opposed. They are made against a randomized number, usually another character’s check result. Whoever gets the higher result wins. An example is trying to bluff someone. You roll a Persuasion check, while the GM rolls a Perception check for your target. If you beat the target’s Perception check result, you succeed. For ties on opposed checks, the character with the higher bonus wins. If the bonuses are the same, roll d20. On a 1–10 one character wins and on 11–20 victory goes to the other character; decide which character is “high” and which is “low” before rolling. Alternately, you can just flip a coin to see who wins.
| TABLE 1.2: OPPOSED CHECK EXAMPLES | ||
| Task | Opposing Skill | Skill |
| Sneak up on someone | Infiltration | Perception |
| Con someone | Persuade | Perception |
| Hide from someone | Infiltration | Perception |
| Win a car race | Vehicles | Vehicles |
| Pretend to be someone else | Art | Perception |
| Break computer security | Technology | Technology |
Trying Again
In general, you can try a check again if you fail, and keep trying indefinitely. Some tasks, however, have consequences for failure. For example, failing an Athletics check to climb a building may mean the character falls, which makes it difficult to try again. Some tasks can’t be attempted again once a check has failed. For most tasks, when you have succeeded once, additional successes are meaningless. (Once you’ve discovered a room’s only secret door using the Perception skill, for instance, there’s no further benefit to be gained from additional Perception checks.)
If a task carries no penalty for failure, you can take 20 and assume the character goes at it long enough to succeed, or at least determines the task is impossible at the character's level of ability.
Condition Modifiers
Some situations make a check easier or harder, resulting in a bonus or penalty to the modifier for the check or the check’s Difficulty Class.
The GM can change the odds of success in four ways:
- Grant a +2 or +5 bonus to represent conditions improving performance.
- Impose a –2 or -5 penalty to represent conditions hampering performance.
- Reduce the DC by 2 or 5 to represent circumstances making the task easier.
- Increase the DC by 2 or 5 to represent circumstances making the task harder.
Bonuses to the check and reduction in the check's DC have the same result: they create a better chance of success. But they represent different circumstances, and sometimes that difference is important. GMs should feel free to take account of very favorable and unfavorable circumstances with bonuses or penalties or DC modifications greater than +2 or -2 (as a rule of thumb, from about +5/-5 up to about a total of +10/-10).
Tools
Some tasks require tools. If tools are needed, the specific items are mentioned in the description of the task or skill. If you don’t have the appropriate tools, you can still attempt the task, but at a –5 penalty on your check.
A character may be able to put together impromptu tools to make the check. If the GM allows this, reduce the penalty to –2 (instead of –5). It usually takes some time (several minutes to an hour or more) to collect or create a set of impromptu tools, and it may require an additional check as well. Characters with the Improvised Tools feat suffer no penalty for not having the proper tools to perform a task. They can make do with whatever is at hand.
Checks Without Rolls
A check represents performing a task under a certain amount of pressure. When the situation is less demanding, you can achieve more reliable results. Applying these rules can speed up checks under routine circumstances, cutting down the number of rolls players need to make.
Taking 1
If your total bonus on a check is equal to or greater than the DC minus 1, you will succeed regardless of what you roll on the die, even under pressure. In this case, the GM might not require you to roll and just assume you succeed, since the task is a trivial effort for someone of your skill. If the check has varying levels of success, you’re assumed to achieve the minimum possible (as if you’d rolled a 1). You can choose to make a roll to achieve a greater level of success, or the GM may assume a greater level of success, depending on the circumstances.
Taking 10
When you are not under any pressure to perform a task, you may choose to take 10. Instead of rolling the check, calculate your result as if you had rolled a 10. For average (DC 10) tasks, taking 10 allows you to succeed automatically with a modifier of +0 or greater. You cannot take 10 if distracted or under pressure (such as in a combat situation). The GM decides when this is the case. Characters with Skill Mastery can take 10 with some skills even while under pressure.
Taking 20
When you have plenty of time and the task carries no penalty for failure, you can take 20. Instead of rolling the check, calculate your result as if you had rolled a 20. Taking 20 means you keep trying until you get it right. Taking 20 takes twenty times longer than a single check, or about 2 minutes for a task requiring a round or less. If there are penalties or consequences for failing the check, such as setting off an alarm or slipping and falling, you cannot take 20 on that check.
Comparison Checks
In cases where a check is a simple test of one character’s ability against another, with no luck involved, the character with the higher score wins automatically. Just as you wouldn’t make a “height check” to see who’s taller, you don’t need to make a Strength check to see who’s stronger. When two characters arm wrestle, for example, the stronger character wins. If two flying characters race, the faster character wins, and so forth. Note this does not include the use of Hero Dice to temporarily increase a character’s score, which can affect the outcome of a comparison check. In the case of identical bonuses or scores, each character has an equal chance of winning. Roll a die: on a 1–10, the first character wins, on an 11–20, the second character does.
Aiding Another
Sometimes characters work together and help each other out. In this case, one character (usually the one with the highest bonus) is considered the leader of the effort and makes the check normally, while each helper makes the same check against DC 10 (and can’t take 10 on this check). Success grants the leader a +2 bonus for favorable conditions. For every 10 full points the helper’s check exceeds the DC, increase the bonus by +1, so a result of 20–29 grants a +3 bonus, 30–39 a +4, and so forth. In many cases, outside help isn’t beneficial, or only a limited number of helpers can aid someone at once. The GM limits aid as he sees fit for the task and conditions.
Types of Checks
You use two main traits for checks: skills and FX:
- Skill Checks: A skill check determines what you can accomplish with a particular skill. It is a roll of d20 + your rank in the skill and the key ability score of the skill against a Difficulty Class. Skill checks sometimes have gradations of success and failure based on how much your total roll is above or below the DC. For example, if you fail an Athletics check, you don’t make any progress, and if you fail by 5 or more, you lose your grip and fall.
- FX Checks: An FX check uses one of your hero's FX as its modifier. It is a measure of what the hero can accomplish with that FX. It is a roll of d20 + the FX’s rank, which measures how strong the FX is, against a Difficulty Class. Some FX do not require FX checks; they just work automatically, while other FX have some automatic aspects and others require checks.
Attack Rolls
An attack roll, whether through a Weapon Group skill or an FX determines whether or not you hit an opponent in combat. It is a d20 roll + your Attack Bonus. The Difficulty Class is your target's Defense, which measures their ability to avoid attacks. If you equal or exceed your target's Defense, your attack hits. Otherwise, you miss. A natural 20 on an attack roll (where the die comes up 20) always hits and may be a critical hit. A natural 1 on an attack roll (where the die comes up 1) always misses.
Resistances
Resistances are efforts to avoid different forms of danger, ranging from damage and injury to traps, poisons, and various powers. A resistance is a static DC based on:
| 10 + the appropriate ability modifier + resistance ranks + any bonuses for feats or FX |
|---|
Constitution is the ability modifier for Fortitude, and Charisma is the ability modifier for Will. Unlike the other resistances, defense and toughness are not modified by any ability score.
Since Resistances are skill checks, there are sometimes gradations to a Resistance. For example, a Toughness resistance against damage results in no damage at all if your opponent's damage roll fails to beat the your Toughness resistance. But if his damage roll exceeds your Toughness, results could vary as widely as a glancing blow, a stunning blow, or an immediate knockout, depending on how much your Toughness resistance is exceeded by.
Condition Tracks
Your character's status is noted across a small number of condition tracks. These tracks are separate, but also work in conjunction with one another, especially those involving FX like Inflict (Condition). As you are afflicted, injured, or otherwise disabled, or when you begin to recover and heal, you note these changes on your various condition tracks.
Injury Condition Track
The injury condition track is used to monitor your character's health. Taking damage from attacks will tend to lower your character's status on the injury condition track, while rest and medical care will improve your character's status on the injury condition track.
Combat Advantage Track
A track to follow what advantages your foes might hold over you in combat, the combat advantage track shows how vulnerable you are at any given moment to different sorts of attacks. Enemies with Combat Advantage over you have an easier time attacking you. You must often spend an action and make an opposed check to reclaim combat advantage.
Action Condition Track
In order to track how able your character is to move and fight normally, the action condition track monitors how many actions your character is alloted in a given round. Effects which alter the flow of time or disorient your character might deny him actions, and recovering from those effects is the only way to regain those normal actions. It is normally a free action to attempt to recover from such a condition each round.
Check Condition Track
Characters often find themselves suffering from conditions which affect their ability to use their skills normally. The check condition track monitors how much of a penalty you may be suffering to certain checks, and which skills are being penalized. It is normally a free action to attempt to recover from such a condition each round.
Movement Condition Track
Finally, some conditions might affect your character's ability to move freely. The movement condition track checks to see how mobile your character is. It is normally a free action to attempt to recover from such a condition each round.
The Combat Round
When things really start happening in a d20 Advanced game, time is broken down into six-second segments called rounds. A round isn’t very much time. Think of it like a panel in a comic book, just long enough for a hero to do something. During a round you are entitled to two actions. You can perform as many free actions and reactions in a round as you wish, although the GM may choose to limit them to a reasonable number to keep the game moving.
One Action
One action generally involves acting upon something, whether it's an attack or using an FX to affect something. You can also use one action to move, or things like drawing weapons, standing up from being prone, and picking up objects. You can take an action to move before or after you take your other action, so you can attack then move, or move then attack. You cannot normally split your action to move before and after your other action, however.
Two Actions
Two actions occupy all your attention for the round, meaning you can't do anything else. Full actions include a full-speed charge at an opponent which ends in an attack, or spending the whole round moving as quickly as you can. Certain powers or maneuvers require a full action to perform, as do some skills.
Free Actions
A free action is something so comparatively minor it doesn't take a significant amount of time. You can perform as many free actions in a round as the GM considers reasonable. Free actions include things like talking (heroes and villains always find time to say a lot during a fight), dropping something, ending the use of a power, activating some powers, and so forth.
Reactions
A reaction is something you do in response to something else. A reaction doesn't take any time, like a free action. The difference is you might react when it's not even your turn, in response to something else happening during the round.
