This game has unused areas.
The Vault is a web-based, retro videogame ARG with live, active communities. It is the first game in the series.
Originally, Contra was intended to be an Easter egg in the Vault. It was designed so that at any point in the game, if a player entered the Konami code a 30 was supposed to appear in the corner of the screen. If the code was repeated a 60 would appear, and so on until maxing out at 99. This number was intended to just sit in the corner of the player's screen until a new session was started. This would mean absolutely nothing, but would rather double as a funny red herring. Unfortunately, due to an impending release date, this was never completed. However, the manual clue had already been sent out into the world.
Grand Theft Auto
Grand Theft Auto's level was never finished. However, the sound was left in the game and can be discovered.