It's really a damn shame it's stuttering so much Cerb, but you'll love the game, i'm sure...
Anyways:
- To begin with, you start the demo with 6 Skill points, to upgrade yourself, to obtain new abilities...
But because you have such a limited amount of skill points, you can't get everything at once, but this adds replay value, so you can try something else...
You can for instance upgrade mellee weapon combat, so instead of only being able of swinging your weapon 2 times, then a little delay, you'll be able to make ynlimited amounts of hits in a row, and you can charge your enemies, while hlding down the fire key, and sprinting at them (of course release attack when approching the enemy) Enemies will get stunned by this, and you can disarm them, by charging your melee weapon, and hitting them... Or you can simply go beserk, after choise
But still, this required that you upgrade yourself before you can perform these advanced actions... Hold your mouse over an upgrade (or weapon in your inventory) to get more info about them
- You don't "choose" what to be as an option, but you choose within gameplay, meaning that you can start sneaking into the first couple of enemies, and slaugter the rest, or perhaps use the environment, or use your magic skills as a combo... The only thing holding you back, is the skill points, because you can't get a perfect assasin's abilites, if you want advanced magic tricks as well... (Freeze takes alot of skill points)
- The "Fire arrow" spell is very different from the regular arrow, set on fire...
Orcs and goblins (don't know about otehr enemies yet, obviously) are not that easy to set on fire with the Fire-arrow spell, instead, it has a slight impact to it, and you can throw several of them after each otehr, and guide them aswell... Normally i don't get to kill and enemy with it, but i get to weaken him, or "stun" him (making him dizzy of the blasts) in just enough seconds to perform a good attack on him...
Now, the regular "bow Arrows" are really cool actually, because it can kill an un-alarmed enemy with one shot in the head, if he's not wearing a helmet or something (Did it with the goblin you first encounter, and got his head stuck to the wood pillar he was standing next to

)
You can also ready an arrow, and go towards any kind of fire, and make it burn... Normal hits will deal with extra damage, and hitting them in the head will set them on fire AND kill them, even if they are wearing a helmet (unlike regular arrows) but again, only if they aren't alarmed...
- The blue bar to your right is the mana-bar, it depletes when using a spell...
Fire arrow spell takes 2 mana per shot, and Freeze takes 7 per shot... Fire Trap takes 10 per "shot" but it's quite lethal and dangerous too, and very effective... Use mana potion to refill up to 100 mana (and you have 20 as maximum, so it will fully refill it)
- Next to your health bar, there is an Adrenaline-bar each hit you give an enemy with a weapon or spell (throwing objects and kicking doesn't count, and killing them by letting them fall off ledges doesn't give you anything either) If the adrenaline bar is full, you can charge a weapon, and it will be an instant kill... (try using daggers from a distance on an enemy while having full adrenaline, then you'll throw it to your enemies throat

You'll automaticly get a negger dagger after this action)
Also, read on weapons, and spells info, about what adrenaline effect they have... Freeze for instance will freeze your enemies permanently, and you can shatter them with any attack (kick, Duke3D style

)
You should read the other as well...
- If you see a rope, connected to some object, try cutting it/arrow it/etc and see what happens, it may trigger a trap

Enemies will do the same on certain occations though
I think this is all you need to now...
I hope you enjoy the game alot, and that you get a new graphic card/PC sometime soon... YOu really should enjoy this game in it's full glory...