Nitrome Must Die

Interdimensional Theory
Nitrome Towers is filled with actual physical enemies spawned by the Charomat. The characters also seem to have their own lives within the building but the only reason why they should be able to physically walk around is if the characters are in some way able to traverse between the different world from the games.

In a Videogame Theory

 * The game is most likely set in a video game despite how it portrays itself in the real world seeing how there are multiple hints to this possibility.
 * Austin Carter's plastic soda cup blinks away from existence giving it the appearance that it's despawning.
 * The whole idea of teenagers putting all the effort to bringing down a company by brutal force is most unlikely to happen since no one has that much willpower to shut down a game company by breaking in.
 * Nitrome Towers is structurally impossible, a strong gust of the wind or a weak earthquake could easily bring a tower that narrow and tall.
 * Game companies do not own a large building mainly for making games, the founder with wouldn't spend that much money on establishing it in the first place, this is if they are really just making games.
 * Most of the interior is infested with wild Nitrome characters brought to life tampering with everything and most of the offices are not safe to be in seeing how there are spike traps everywhere.
 * The tower is larger on the inside.
 * The points above are meaningless unless NMD was just an exaggerated metaphor of really bringing Nitrome down.