In the last post regarding the project I stated that we used some assets from Gears of War but after putting them inside the level we were unable to create a working game build any more. We looked over every aspect of the game that had changed alongside the "new" assets but could not find anything wrong that would indicate a solution to the problem. We asked around other students and even some teachers until one of the teachers looked at our packages and noticed the Gears of War packages. He suggested removing the GoW assets and try building again. It worked!
Even if the editor is able to use packages from licensed games the game build might not work with them. He even said that packages saved with other versions of the UDK might not work properly or cause problems so we have to create new packages if we would change the UDK version.
As a result, we have no corpses in the level at the moment and the artists had to create their own sand sack barriers. Maybe we will use parts of our character or creature models as corpses later on...
Another aspect that changed is the HUD, it now only contains the cross hair and the ammunition indicator. Some text for the objectives will be implemented in the next few days and after that the HUD will be final and only the level lighting and the character model implementation (the model itself is finished and has most of its animations already) has to be done before the final polish.