1. I undestand that wearing heavy armor makes it harder to use your skills. But why the hell does it affect faith and knowledge ??
Because weapons and armor were powerful status symbols. A chain mail shirt cost as much as 4 or 5 slaves, so everyone who saw you wearing one knew immediately how extremely rich (therefore, successful / powerful / mighty) you were. Besides, good clothes make you feel good; the same should apply to arms. Additionally, good arms ought to give you confidence (faith) in your ability to defeat all foes. (However, it's a kind of bug that your knowledge-skill also rises (if it does) - got to check this.)
2. Could you tell me, when my skill and the skill of my enemy are equal - what is the chance of hitting in combat? 50% ?
Your attack skill is set against your opponent's defense skill (randomly chosen, either shield / parry / dodge). When both skills are equal, you ought to have a 55% chance of hitting (odds are tilted a bit in your favor to make sure you don't get killed too easily).
3. Is it actually possible to defeat warriors of Thoralf's brother, after slaying him?
(just curious )
If you mean these people who attack you on your way between two villages in order to take revenge: No, you can't defeat them, for technical reasons. (Other people would have to react to your killing of such an important person - that means, I'd have had to write dozens of additional dialog passages - every NPC for every main character you might have killed. By making sure you can't reach other villages after killing a main character, I only had to take care of the NPCs in that same village.)
4. Is there a time limit? Or can i wander, fight, trade endlessly and the plot doesn't break?
endlessly; the game is purely event-driven. While that may not be perfectly realistic, I think it's more fun that way.
5. When do you plan to relase second part?
I'll start work on it as soon as I've finished and released DARGHUL, the Teudogar-engine-based fantasy RPG I'm currently working on: That'll probably take me at least about 8 more weeks of work.
6. after hours of fighting, when my combat skills were quite high (very good), strength,dexterity and intelligence were still fair/avg/avg. (i've also mastered all demo spells). Does it mean that character progress in the demo is limited? And if so, it will me major disadventage when using these saves after upgrading to full version...
No, that hasn't got anything to do with Demo/Full Version. Your character development in Teudogar is reflected mainly by your skills, while your attributes (STR/DEX/INT) improve only slightly and very slowly. The basic idea was that if you've got an I.Q. of 110, you'll still have an I.Q. of about 110 after graduating from a university - e.g., you can easily and comparatively quickly improve your skills, enabling you to make better use of your mental or physical capacities, but it's very hard and takes many months or even years to change these latter.