Fridge Horror: The invisibility is spreading: the food Nick eats turns invisible, and we see parts of the Magnascopics building where Nick was sleeping that are visible briefly, then it spreads to the parts of the building that remain visible. We never see the area where the building is after that scene, but it can be assumed (since there is no evidence to the contrary) that the invisibility will continue to spread, not just on the surface but into the earth's crust. And the one person that was in the best position to put a stop to it was murdered by Jenkins.
Narm: Nick furiously demanding "I want my molecules back!" of the scientist who was head of the project that inadvertently rendered Nick invisible. In context, it's supposed to be dramatic, showing a bit of Sanity Slippage as Nick is running out of options to become a normal person again. Between the absurdity of the sentence itself as well as the fact that Chevy Chase didn't succeed at Tom Hanks Syndrome, it comes off as ridiculous.