Yes, it's RPG and it's a standard fantasy-medieval setting with a few sci-fi elements

Might and Magic 7, golem collection.

It came to my mind when you mentioned body parts, but I dismissed it because building the golem is in no way crucial and hardly something that has to be done quickly. Plus, I was under the impression it's an adventure.

The sci-fi elements reminded me of it again. And now I understand what you mean about having to do it quickly. Building the golem has a nice side effect. "Promotion" and all that. 4 mages in your party? Or 3 mages + cleric?

4 elven female sorceresses :D I've made a similar playthrough years ago choosing the dark side but now I want to choose light side. At that point of the game it's rather difficult, my ladies die fast but it's doable.

EDIT: your turn obviously :D

I can't think of anything at the moment, so anyone please feel free to take my turn.

To keep things going:

It started pretty badly as I found a body of a friend. Sorry pal for not paying any respect to your body but I had to do it, this way it would be possible to find out what had happened to you!

Where did you find it? Was it an apartment, some warehouse or, perhaps, a train?

A train ;)

Good, so it's probably the game I was thinking of. Now to remember its name... (-_-)

Update: Ha! Got it! The Last Express.

Of course! Great game

Your turn

Thank you.

"You know, brother, life's a funny thing: one moment you're struggling to prove that someone dear to you was falsely accused - and the next you have to fight him. I came out victorious, but it didn't go that well for me; I ended up powerless and with one of my old acquaintances dead. What do I have left? Despair... and my faithful blades."

This sounds maddeningly familiar, but I can't pinpoint it. To help narrow things down, is the game on GOG?

Yes.
I have it both in my Steam and GOG libraries.

Could you tell something about the genre and settings?

EDIT: and a wild guess: Dust: An Elysian Tail?

Yep. :-)
Your turn.