Newbie/Starting tips?

[Zorro]

Sooo, i just started playing the game but i have a few doubts, like:
- How do you heal?
- How do you "collect souls"?
- What is gold for?
- What are holy items for?
- Can't you crouch?
- Do you get something for "gibbing" (blowing in pieces) enemies?
- Pretty sure you can do something interesting with the spinny blade weapon, but i still can't figure it out.

[Telephone]

You heal by picking up souls dropped by enemies - the green ones. On difficulties under Trauma, they drop green souls which heal 1 hitpoint. There are also differently coloured souls which heal more HP.
Collect souls by touching them.
Gold is for using Tarot card powerups. You need money to equip them.
I don't think you can crouch, nor do you need to.
If you use the spinny blade weapon and rightclick corpses to juggle them around, they drop money. That's close enough to your gibbing question. Otherwise, it's fun to do.
I think if you hold left click then right click, it'll launch the blades. Some weapons have a tertiary fire like that, try them all out!

By the way, I recommend playing on at least Nightmare on your first playthrough. Trauma gets you a different ending.

[Zorro]

@optimuswhat Ah thanks a lot m8, i would have never guessed the tertiary fire thing.
Also, is Trauma like, the "real" ending or something? Because first i started a playthrough on Nightmare (in which enemies did drop the green things) but then i started a new one on Trauma before even finishing the first level since it's "Painkiller's true story" according to the game.

By the way, is it possible that at the beginnig of each level my secondary ammo for each weapon gets set to 0?

[Telephone]

Trauma is not the canon ending considering the expansion pack of the game, Battle out of Hell. I think the "True Ending" thing is just some idea the developers had before the game took off. An attempt to not leave a cliffhanger I suppose!
Trauma also locks you out of the last chapter of the game because of story reasons. There's a mod to rectify this though.

I don't know what you mean by secondary ammo getting set to 0. It normally starts at some number.

[Peppins]

About healing, you can also find the Megahealth on some levels in a secret zone and on daydream and insomnia will be restored on checkpoints. About spinning blade (painkiller weapon) you can attack enemies and destroy them in pieces. If you grab them some time with secondary fire you get some golds. Each levels have also lot of object that you can destroy for golds, and also secrets that you can find and get golds too.

@optimuswhat: all weapons, except rocket launcher, have primary fire, secondary fire and combo fire.

For more info: https://painkiller.fandom.com/wiki/Weapons