Delta Return Made By The-Real-Game 

Story :

 It's been five long years since the Delta Research Facility incident, in which you obliterated the original facility. We had yet to hear anymore from the facility until now. As you will know a few days ago there was a security breach at our research plant, in which one of the leaders of our main *Classified* project was abducted. Well we've now traced the abductors, it appears they're from the Delta Research Facility.

 It seems the facility has now been rebuilt; they have received funding from an unknown source, which we are in the process of tracking down. Your mission is to infiltrate the facility once again and rescue our project leader. Be warned that the base is strongly guarded by soldiers and a variety of other creatures.