Stalker Online documentation
Characteristics/Stats
Force/strength
Intelligence
Dexterity
Stamina
Perception
All characteristics start with 5. Max characteristic level is unknown. Some skill blocks(defined later) increase characteristics like Perception. These blocks state up to 2 levels are available. I think this means 2 levels maximum increase (i.e, 5+2=7 max levels from skill blocks) but this is not known.
Skills
The 3 main skill sets are Fighting(6 sub-skills), Survival(5) and Support(6). All skills are linear. There is no branching of skills. Skills are innate or passive. They do not require activation.
Each of the 3 main skill sets have their own experience point pools. Experience points are earned by using the skills within that skill set. Experience gained while using a rifle results in Fighting skill set experience points. Experience points to level up do appear to increase with each level. Level 2 is earned at 1,000 points. Lvl 3 is in between 2,300 and 2800 pts. Lvl 4 is, so far, more than 5400 XP.Other levels are unknown.
When you gain a level in a skill set such as fighting, you get 15 Skill points to spend on skill blocks.

A skill block is similar to a skill level. There are several skill blocks that can be leveled up per avatar characteristic. It varies how many blocks each avatar characteristic has. Reason unknown.
Sub-skill sets have 12 earnable block levels. Each skill block requires spending 10 skill points. You start with 10 points in all skills. Different sub-skill sets (e.g., Fighting:Light weapons) have skills earned at different block levels. Important: Skill points can not be redistributed. Once you assign a skill point it is spent and can not be re-assigned.
Fighting skills
Light weapons
Quick draw/aiming(?) w/light weapons
levels: 1
required skill level: 10
should not cause you to Duel
??????????/dostavaniya(Aiming?) speed of light weapons is increased 30%
Rapid reload - pistols
levels: 1
required skill level: 20
30% fast reload
Perception increase
levels: 2
required skill level: 50
+1 to perception
Throwing**
Throw grenades farther
levels: 1
required skill level: 20
quick grenade
levels: 1
required skill level: 30
Throw 2 grenades at a time
Force/strength(?) increase
levels: 2
required skill level: 50
+1 to force
** the Skill block locations for the first 2 sub-skills are one level deeper(block 3 instead of block 2) than the other sub-skill sets but the number of points you have to spend is the same as the other sub-set's block location. A possible error for these 2 skills either way.
Assault Rifles
Quick draw/aiming(?) w/Assault weapons
levels: 1
required skill level: 10
30% faster draw/aiming(?)
Rapid reload - assault weapons
levels: 1
required skill level: 20
30% fast reload
Perception increase
levels: 2
required skill level: 50
+1 to perception
Rifles and shotguns
Quick draw/aiming(?) Rifles and shotguns
levels: 1
required skill level: 10
30% faster draw/aiming(?)
Rapid reload - Rifles and shotguns
levels: 1
required skill level: 20
30% fast reload
Perception increase
levels: 2
required skill level: 50
+1 to perception
Camper
you're a tree! better aim while standing still
Shooting on the move
Stamina increase
levels: 2
required skill level: 50
+1 to stamina
Heavy weapons
Quick draw/aiming(?)-heavy weapons
levels: 1
required skill level: 10
should not cause you to Duel
??????????/dostavaniya (Aiming?) speed of light weapons is increased 30%
Rapid reload -heavy weapons
levels: 1
required skill level: 20
30% fast reload
Force/strength(?) increase
levels: 2
required skill level: 50
+1 to force
Survival skills
Physical training
Marathon
levels: 1
required skill level: 10
the best self-defense art,
running increased speed by 20%
Thick skinned
levels: 1
required skill level: 30
Reduced damage by 20%
Stun resistance
levels: 1
required skill level: 40
You're head is as hard as a rock
Stun resistance increased 20%
Force/strength(?) increase
levels: 2
required skill level: 50
+1 to force
Anomaly detection
Intelligence increase
levels: 2
required skill level: 50
+1 to intelligence
Detection(of sneaking?)
Perception increase
levels: 2
required skill level: 50
+1 to perception
Metabolism
Fewer Adverse Effects
levels: 1
required skill level: 40
exposure time to negative effects is reduced by 30%
Stamina increase
levels: 2
required skill level: 50
+1 to stamina
Disguise/sneak(?)
Harder to be seen (at night?)
levels: 1
required skill level: 40
At night you could steal a piano without being seen.( decrease in being visibile)
Agility increase
levels: 2
required skill level: 50
+1 to Agility
Decrease the visibility of heavy weapons
levels: 1
required skill level 50? (probably 60)
Howitzer in your pocket?
No problem!
Decreased in being visible when using heavy weapons
Support skills
Repair
Repair simple things
level 1
required skill level: 10
You can fix simple things
Repair the usual things
level 1
required skill level: 40
Requires: Fixing Simple things
Intelligence increase
levels: 2
required skill level: 50
+1 to intelligence
Repair complicated things
level 1
required skill level: 70
Requires: Repair the usual things
Repair everything
level 1
required skill level: 80
Requires: Repair complicated things
Modification/Creation
Create simple stuff
level 1
required skill level: 10
Create normal stuff
level 1
required skill level: 40
Requires: Create Simple things
Intelligence increase
levels: 2
required skill level: 50
+1 to intelligence
Create complicated stuff
level 1
required skill level: 70
Requires: Create normal things
Create anything
level 1
required skill level: 100
Requires: Create complcated things
Accuracy
Accuracy with light weapons(Start with)
level 1
required skill level: 0
reduced wear on pistols
Accuracy with Rifle/shotguns
level 1
required skill level: 10
Reduced wear on Rifle/shotgun
Accuracy with Assault weapons
level 1
required skill level: 20
Reduced wear on Assault weapons
Accuracy with Heavy weapons
level 1
required skill level: 30
Reduced wear on heavy weapons
Agility increase
levels: 2
required skill level: 50
+1 to Agility
Packaging
Force/strength(?) increase
levels: 2
required skill level: 50
+1 to force
Increase maximum weight
levels: 1
required skill level: 60
Increase carry weight by 10
Medicine
Good doctor
levels: 2
required skill level: 40
here! scar is almost invisible!
positive effect of the drugs increased by 20%
Intelligence increase
levels: 2
required skill level: 50
+1 to intelligence
Battle surgeon
levels: 2
required skill level: 60
positive effect in the treatment of others increases 40%
Good luck
Decreased chance to drop ammo
levels: 1
required skill level: 30
I have everything written down!
Ammo drop probability decreased 30%
Decreased chance to drop weapons
levels: 1
required skill level: 40
MINE! Weapon drop probability decreased 30%
Decreased chance to drop loot
levels: 1
required skill level: 60
Inventory drop probability decreases 30%
