I struggle because I can't finish anyone off in a big group. Not sure if I'm supposed to just press triangle when it appears or turn analogue stick to face attacker as I do it.
I'm sure it will get easier as Kainz said but at the moment a big group is a challenge.
Just press triangle. The character turns once you press triangle. Soon as you see an Orc lift their arm press triangle. This early on you have to be patient with the battles. Block, hit or double hit then block until you slowly clear them out. No orcs try to hit you at the same time. Which is a shame. It would have been interesting to see the player rolling and blocking as multiple orcs swing at you.
Oh and make sure you get the poison rune. I remember first coming across levelled up captains as he kept killing me with his poisoned weapon. He ended up level 20. Battled hardened and everything. He practically had zero weaknesses. Wished I recorded that big fight I had with him because I got so sick of being killed by him with so little runes so I went on a rage battle to get him. Two captains came walking in while I was battling with him. I was ready to run away at that point but decided to ride it out, battle away and see what happens. Once I killed the other captain some of his fears got exposed making the fight just a little easier. Must have taken 40 - 50 minutes that battle. Honestly didn't think I was going to make it. The 3rd ran for it.
You will likely have a stalker in the game at some point.
Also, don't be scared to run away. The strongholds they just keep coming for you. I think I ended up with another stalker at one point. Some orc cook that was a fast runner. Mean ugly git. He too was level 20 with hardly any weaknesses.
Keep an eye out for the caragors early in your stages as you'll want to run for it once they've spotted you in fights. Roll many times if they do.
The stealth missions were my favourite for the game.