I have a few questions this game series...

1. When I buy items from a shop or vendor in game, do they eventually run out of stock? And if so, how often do they restock items?
2. How does the lockpicking skill work? I am playing a rogue, and when I tried to open a lock, a window came up with a few lock tumblers but I don't know what to do at that point.
3. Do enemies respawn?
4. In this game, is there much grinding involved?
5. Is there a screen I can access that shows all the keyboard commands?
6. I read somewhere that if you come to a locked door but don't have the lockpicking skill, it is possible to kick a door in. Is this true?
7. Are items I find in a chest random?
8. Is there much replayability?

Any help is a appreciated! Thanks so much!

1. Yes the thing you buy are gone from the shop and things you sell will be available there for a few days or weeks. Don't know how long exactly. Every month or so they merchant's inventory will change again.

2. You do nothing and wait if it worked. If not you can do it again but sometimes your lock pick will break so you will run out of lock picks eventually

3. Nothing respawns in this game. But if you rest and camp then in most areas opponents can spawn

4. No grinding is involved

5. Yes there is. But I don't remember what it was (Esc or one of the F-keys)

6. You can break door or chests open. But your weapon can get destroyed by it by random chance

7. All loot is generated randomly (afaik based on your level and what chest type it is)

8. No. There are only 2 viable playstyles imho: Pure fighter or pure mage. Mage is way easier than everything else but only if you know exactly how to generate a pure mage. But until you find this out the game is unbelievably hard. After you know what attributes you have to increase at character generation the game is just a cakewalk.

I agree with pretty much everything Randyandy said.

If you're going to bash open a chest or a door, a blunt weapon like a hammer works a lot better than a dagger or a sword.

I like the game quite a bit, but it's unforgiving in some ways.

My experience is limited to halfway through book 1.
Well, most containers have random contents and unless you have opened it already the content is spawned at every mapload, so you can cheat a bit if you save before opening a box.
Some containers have a set loot. That's mostly for those containing quest items.

For the play style, I like my fighter with lots of support magic (bless, cats eye, leather/stone skin, predator sight...) and basics in pick lock and skulduggery.