The basic idea: Each condition has up to three levels. If you cause an effect (via magic or similar abilities, but not poisons or extraordinary abilities) that would normally bestow the second or third level, and the person fails their save by 4 or less, they take the first level instead. Likewise, if the effect would bestow the third level, and they fail their save by at least 5 but less than 10, it bestows the second level instead. The spell can never bestow a more extreme effect than the rules say.
If someone is already suffering from the first-level condition, each of these numbers is reduced by 2 (so failing by 1-2 has no further effect, failing by 3-7 bestows the second level, and failing by 8 or more can bestow the third level.) If someone is suffering the second level, failing by 6 is sufficient to bestow the third level. This does not apply to certain conditions, noted below.
If the save is for a partial effect, the effect that occurs on a save will always occur, regardless of condition levels.
And now for the condition types (Core material only):
|Condition||First Level||Second Level||Third Level||Examples|
|Visual Impairment*+*||Dazzled||Blurry Vision||Blind||Flare, Glitterdust|
|Charming||Trusting until save||Charmed until save||Charmed||Charm Person,Command Undead|
|Compulsions***||Effect 1 round||Effect until save||Normal Effect||All Enchantment(Compulsion) and Illusion(Pattern) spells not under another category, Control Undead|
|Sleep||Drowsy (as Lullaby spell) 1 round/level||Sleep until save||Sleep||Lullaby,Sleep,Deep Slumber|
|Unconsciousness||Staggered||Stunned until save||Stunned or Unconscious||Color Spray|
|Blindness||Blind 1 round||Blind until save||Blind (normal duration)||Color Spray,Blindness/Deafness|
|Fear||Shaken||Frightened or panicked||Damage,possible death||Cause Fear, Scare, Phantasmal Killer|
|Deafness||Deaf until save||Deaf (normal duration)||N/A||Blindness/Deafness|
|Movement impeded||Staggered||Slowed (as the spell)||Paralysed||Ghoul Touch,Slow (but not Hold Person)|
|Nausea*||Sickened||Nauseated until save||Nauseated||Stinking Cloud|
|Tiredness*+*||Fatigue||Exhaustion||N/A||Touch of Fatigue, Ray of Exhaustion|
|Curse***||20% effect||50% effect||Full effect||Bestow Curse|
|Planar Travel****||Travel to native plane only||Travel to any nonhazardous plane||Travel to any plane||Dismissal, Banishment, Plane Shift, Maze|
|Feeblemind*+*||-2 to INT and CHA for 1 minute/level||1d6 INT and CHA damage, 50% arcane spell failure chance until key ability is fully healed||normal effect||Feeblemind|
|Soul Manipulation****||Dazed 1 round||Dazed 1 round, save again following round||Normal effect||Magic Jar, Trap the Soul|
|Harmful bodily transformation**||5d6 damage||1d6 damage/level||normal effect||Baleful Polymorph, Flesh to Stone, Implosion|
|Energy Drain****||1d4 negative levels||1 negative level/caster level||Death||Enervation, Energy Drain, all necromancy death effects|
And now some explanations of things found in the table (not including what's already in the rules or self-explanatory):
Blurry Vision: The creature isn't quite blind, but can't see clearly. All enemies have concealment, and the creature has -10 to spot and search checks.
Trusting: The creature gets -2 on Wisdom checks and Sense Motive checks against the caster
Until Save: The creature gets to make a new save each round as a free action (at the end of their turn); on success, the effect is broken. The effect also ends after its duration is up, as usual.
X% effect: Numerical effects are rounded to the nearest whole number (or up if it's right in between.) Non-numerical effects have that chance of applying each round (so a "50% to take no action" curse at 20% efficiency would cause the creature to fail to act 10% of the time.)
Planar Travel effects: If the plane the target would be sent to does not fulfill the criteria, the spell fails. A hazardous plane is one with enviromental or planar effects that cause some sort of harm. (Enviromental effects present on only a small minority of the plane don't count here.)
*All stink-based Nausea effects are also blocked by Delay Poison and immunity to poison. Distraction-based nausea effects are not so blocked, and are not affected by the condition levels system.
**The target may choose to take the normal effect instead of damage. If it takes damage, the reduction to the failure needed for a higher level lasts for 1 minute/caster level, and applies only to the exact same spell.
***Lower levels make higher levels easier to attain only for compulsions and curses with the same effect.
****Lower levels do not make higher levels easier to attain (except by penalizing saves).
*+*Different versions of this effect do not stack. Only the most powerful applies.
In addition, there are a few offensive spells, even in Core, that need fixing in other ways, so I'll put that here too:
Grease: When you are on a slippery area (such as a Grease spell or ice), Balance checks are necessary but you are not considered to be balancing for purposes of losing DEX bonus to AC.
Ray of Enfeeblement has a Fort save for half. Waves of Fatigue has a Fort save to negate. Waves of Exhaustion has a Fort save to reduce the effect to fatigue, or exhaustion if the target is already fatigued. Energy Drain has a Fort save to only take 1d4 negative levels.
When determining whether a Web provides cover, use the normal rules for determining cover. Thus, a creature on the edge of the web has cover from opponents outside the web, but they do not have cover from it. For determining total cover, use the normal rules for determining total cover.
Black Tentacles do not regrapple a creature that escapes them.
It is possible to move through Solid Fog with a Strength check (but not an Escape Artist check) as if it were a Web spell. You may first roll the check and then decide whether to use the check or move 5'.
Maze has a Will save to negate, but at a -4 penalty.
Imprisonment has a material component: A powder composed of diamond, emerald, ruby, and sapphire dust with a total value of at least 10,000 gp.