Fraekke wrote :
4. Force open - not sure how NOT to get this one, but that might be a bug - it obviously has something to do with the crowbar and the locked dor.
It's quite obvious, isn't it? You force the door open with the crowbar. The only problem here is that the game doesn't reset the items properly (i.e. you keep items after a restart). In your first playthrough you'll find the door locked and continue on to find the crowbar, but probably without turning back. Now because the items don't reset, in all consecutive plays the door can be opened.
6. ?? Havent gotten this one yet!
I haven't found anything about this achievement in the decompiled sources. It doesn't appear to be referenced anywhere...
Edit:
With some more hacking I got the game to show me the 6th achievement, it's called 'Playing with candles'. Quite obvious where it should trigger, but it is missing the code for it. As noted in my original post it is a requirement for the 3rd ending, so that one is effectively unreachable.