The software is copyrightable, the displays are copyrightable, the cheat book is copyrightable. Making a profit from copyrighted works without permission is a federal crime.

Other IP laws include “unfair competition” and there could be a claim that Morgan Corp has “stolen” the ideas for the game from Nicholas and misrepresented them as its own development.

Similarly, the Nicholas game probably has a distinctive “look and feel” that could be perceived as an indication of the source and quality of the game, thus becoming a de facto trademark (or trade dress) owned by Nicholas. Under the federal Lanham Act (and similar state laws), there would be a claim for trademark infringement, even without a trademark registration, if the game was “used in interstate commerce” with the distinctive look and feel attributable to Nicholas.

You do not need to register copyright in order for it to be valid.