As defined by Oxford Dictionary, a noun is a word used to identify people, places, things, and ideas. Since a complete sentence in the English language requires a subject and verb, nouns are very important. The subject of a sentence is always going to be a noun; and therefore, is very important to understand its usage. See examples of noun usage below from my playthroughs of various video games. MAKE SURE TO TURN ON "CLOSED CAPTIONS" TO VIEW NOUN EXAMPLES.
Note: Look to the RIGHT of each clip to be aware of the game's ESRB Rating.