Hi.

I've been playing regular blood coop with a friend by using the "Multiplayer" shortcut.

I want to play Cryptic Passage in coop too. How can I do it?

Open your COMMIT.DAT file with notepad and rename the entry
LAUNCHNAME = "BLOOD.EXE"
to
LAUNCHNAME = "CRYPTIC.EXE"

I've not tried it before but you could probably put in the BMouse launch line here if you want to use that.

I doesn't work. It appears that COMMIT.DAT is being overwritten back into BLOOD.EXE by something.

Sorry, I forgot, the Multiplayer link launches SETUP.EXE which will overwrite COMMIT.DAT. After you've made the change in COMMIT.DAT, in your dosboxBlood_multi.conf file, change the [AutoExec] section that launches SETUP.EXE to COMMIT.EXE

It worked! We got up to the Gothic Library level. For some reason, the textures in that level are wrong. The new textures showed up correctly in the prior levels though...

Fun. Cryptic.exe should have renamed the cryptic passage art files, but to do that manually...

REN TILES007.ART TILES007.AR_
REN TILES015.ART TILES015.AR_
REN CPART07.AR_ TILES007.ART
REN CPART15.AR_ TILES015.ART

And then do the reverse when you want to revert back to normal Blood

REN TILES007.ART CPART07.AR_
REN TILES015.ART CPART15.AR_
REN TILES007.AR_ TILES007.ART
REN TILES015.AR_ TILES015.ART

We replayed the Gothic Library today and the textures were fine. We got up to the cemetery map and the textures began corrupting again... Seems like you have to restart the game after 2-3 levels...

That should not happen. CRYPTIC.EXE will only revert the textures when it gets shut down. I can only think of that maybe you somehow have had only either of the art files renamed, so you keep having one vanilla Blood one and one Cryptic Passage one, despite the renaming.