From the elevator opening to the PlayStation console on the desk in reference to Shadow Moses, the game made good use of it's Shadow Moses/Umbrella Corp crossover well. Several of the dead soldiers were modded snake skin models, and the main character skin was a modded version of Leon's from RE2 and Solid Snakes from MGS1(PS). I think even the lockers were reused in this game, as well as the way objects would blink and disappear after being shot off a shelf.