There is a chain on the walkway that opens up nearby wall (highlighted red on the map) that leads to a key needed to open the door to the exit. The chain cannot be pulled.

In order to finish the level you can still use Open Door spell on the wall. You can do that by standing to the right of the inactive chain and casting the spell while looking ahead at the wall.

A fix for that would be welcome.

Can confirm this,also had that Bug.

ETTiNGRiNDER has an IPS patch (that I have not tried) which also includes a fix for the ungettable bow on level 13.

Witchaven 2 patches are available there for (coincidentally) Level 5 and 13 as well.

https://ettingrinder.youfailit.net/wh-tools.html

Do You mean in the original version? In the game folder there are two versions, the Ettingriner and the classic one, shouldn't be those bugs fixed at least in in the Enhanced version?
The Ettingrinder patched version is launched by default as far as I know and my experience.

I also confirm: stuck at Map 5 (in the enhanced version), the switch does not work and it is impossible to retrieve the brass key.

The chain is not interactable.

This is a big problem, please solve it.

It's not a problem, it is the way the game was designed....if you did not safe some "door open" spells, then you will face lots of situations like this during the game. Quick solution? backspace, then type mommy and press enter

But Mommy does not give you "door open" spells. I tried it (in the Enhanced Edition version).

How can this be a solution?

For some cases I'd allow for argument as to the map designers' intent, but the chain on level 5 not working is almost certainly a bug. There's a sector right near it that was tagged with an action, but didn't have the activation chain properly linked to it.

I think the chain is "fixed" in BuildGDX because I don't remember using an open door spell on map 5.