This is the official Coop map for Painkiller: Resurrection. It is not compatible with the original Painkiller.
How to start Tower of Power as Coop map:
Start Painkiller Resurrection.
Create the new multiplayer game.
Select FFA gamemode.
Set the timelimit and add the DM_Coop_Tower_of_Power map to an empty map list.
Start and enjoy!
How to start Tower of Power as singleplayer map:
Start ResurrectionEditor (the Painkiller Resurrection\Bin folder).
Click File, Load level and select DM_Coop_Tower_of_Power.
Click the blue triangle and press F10 key.