Hi Seren, thank you a lot for generous list, already tested some levels and they're exactly what I was looking for - many thanks!

Regarding my version - I know that "standard" installer contains vanilla JJ2: Secret Files, but we're using for 100% JJ2+ version, which is present in "extras" in GOG's download. My brother, when he was playing alone, was initially using the "vanilla" version, but I told him to download "plus" version from extras. Up from this moment all of us are playing in the same version.

It even has in the corner (in main menu) info about version (quoting: "JJ2+ Beta v5.6 (2018-02-26)). Is it possible that this particular version can have some issues, or it's rather unlikely?

https://i.imgur.com/Z3r7J6z.png