I am quite confident in my game so far. I have decided to remove the 'enemies attacking' aspect from the game as I have begun to make my game and the enemies do not fit well. However I still believe I have a good idea on the game itself. It will stay a first person game however now it will not includes enemies only a timer.
Here is my link to my GDD which includes more details about my game.
I am still working on some details for the game but they are minor details such as the home screen graphics, end screen graphics and music. As mentioned in my GDD, I have a simple idea for the opening home screen. I am not fully set on this idea but I do want to keep it simple and include some low, eerie music in the background along with a ticking sound.
Opening Screen Idea. (Source)


