Was searching around filefront and found this!: http://www.filefront.com/12738418/Blood-2-Coop/ . Yep thats right. I played it for only a few seconds, expecting a thousand glitches, but no glitches. It worked very well...until this(unrelative to the coop mod) mfc error came up: http://www.gog.com/en/forum/blood_series/client_mfc_application_has_stopped_working_error_with_blood_2 . Have fun playing coop!
PS: If one of yall find a coop version of "the nightmare levels" im sure everyone would love you long time.
EDIT: If someone makes a list of the levels in the correct order, it would be well appreciated.

For real I'm going to buy it right now.

I disagree. I played this more in detail and there are pratically no problems. The only problem I have found is loading to the next map. I believe you need to have all the maps ,in the correct order, in the map list when creating the server. So, when you finish a level it goes to the next level no problem. There are two things I dont know of though. I dont know if bugs are created when playing over the internet ,because I have only played through LAN. And finally, I dont know if your talking about the game being suckish or that this map pack is having errors. The game is really not that bad.