After finishing the chatper 1, where each character was played separately, chapter 2 introduced all three characters at once. While one can switch between characters explicitly, they also switch between each other in some erratic and half random fashion. This makes the game extremely confusing - you can't even focus during combat, since characters constantly switch between each other. Is this normal, or I'm hitting some kind of weird bug?

I'm playing the game in Wine 1.7.6. on Linux.

This has never happened to me, so I'm pretty sure it's a bug. Are you playing with keyboard and mouse, did you apply the update and are you sure you're not accidentally swapping characters?

I configured all keys to be on keyboard, so I'm not using mouse. I applied the update as well (I can try reinstalling it just in case). I'll give a try to an older version of Wine as well for a test. I'm not swapping characters for sure.

never happened to me too, anyway I played only on windows

Don't bind movement to the arrow keys. Character selection is apparently bound to those, something which is not documented or mentioned and, as far as I am aware, not changeable. I assume it's hard-coded or something.
It's pretty much one of the worst pc ports I've seen in a long while.

Thanks for the hint! I'll give it a try with different binding. It's weird though - arrow keys are natural to use for movement for keyboard only game... If this is indeed the case you are right - it's a poor port. Is there any way to file a bug to developers? We can also file one for GOG to facilitate this.

Both the original developer and the studio that ported it went down some time ago, but even then, I don't think either the studio or the publisher would care about an obviously rushed port from 2004.
GOG generally only makes sure the game is functional (which this one, technically speaking, is... barely) and doesn't, probably can't, meddle with the actual game.

If you have got a gamepad, I suggest using that, since the game was meant to be played with one.
Otherwise, try to find a non-arrow setup that is comfortable.
Personally I gave up on the game. The controls were the final nail in the coffin of a game that couldn't even bother to have any in-game options beyond 'subtitles on/off'.

I suspect if the keys are hardcoded, that can be modified right in the binary (without breaking it) to some other keys just using a hex editor, freeing arrow keys for movement. Of course one will need to figure out where that is hardcoded. Just a guess. This kind of a job suits GOG well. I think the bug is pretty serious for GOG to consider, if you even stopped playing the game. Feel free to ping GOG's support, it won't hurt if they'll say they have no resources or interest to fix it.

nvm, that's what shmerl said.

Just want to be sure it's not Wine specific, because I never played the game on Windows. I don't want GOG to reject the request saying that they don't support Wine cases :) If the bug is present in Windows for sure, I'll file a request to them.

As a thought, may be keys can be found and modified with some resource editors for Windows DLLs....