Plot hole: When Dr. Marvin is trying to get Bob to leave the night before his television interview, he can't leave because it's pouring rain. He also can't drive him because their car was left at the boat dock. However, Dr. Marvin could have easily called for a cab to drive Bob back to where he's staying.
Suggested correction: This assumes that there is a taxi service in the small town in which they reside.
This is obviously a tourist town, which would likely create the need for a taxi service.
It also seems to be a fairly secluded and very rich tourist town with cars almost necessary to get around.
Suggested correction: At that time of night in that condition, I highly doubt calling a taxi cab would be easy, especially since Bob lives right down the road, no taxi far away would come just to drive someone a short distance like that.
Plot hole: When Freddy causes Carlos' hearing aid to be incredibly sensitive to the slightest sound, the sound of water droplets and pins falling is exceptionally painful. However, the sound of Carlos speaking or even Freddy's shushing him doesn't cause any discomfort despite those sounds being vastly greater than the previously mentioned sounds. (00:36:15 - 00:37:19)
Plot hole: In the first film, Toulon fled to America and, when the Nazis found him, committed suicide in 1939. But this movie, effectively the prequel to the franchise, opens in 1941.
Plot hole: When the military says they're going in, they ask how Billy got off campus through a pipe. Earlier when Billy goes through the pipe he's immediately met by two soldiers in ghillie suits. You mean to tell me the soldiers that meet Billy wouldn't know how to get through a pipe? The military is incompetent in this film but come on.