Then wear the developer hat and apply details to each entry, explaining how you will achieve that through programming. (Don't do them all at once)
By that time, you can start implementing bits. Like 0r0d says,
With that in mind, think general game loop, UI, display modes and file I/O.
The high-level stuff is what will be hardest to change later, so it's worth thinking it through first.
Then think about the concepts elevating the application into a game. (create a level format etc.)
It's nice to get back to that list. At first it might be a pencil thing, but this could eventually end up as your roadmap.
I love lists...
The time taken to think about something before doing it usually pays off.