A shooter!
It took me two days, but I finally figured out what kind of game I want to make. Remember "Into the Eagle's Nest"? Or maybe the more recent "Alien Breed" series? So yes, something like that, only with dots.Of course the display will need to scroll, and to double (or even triple) the number of colors, I will have some of the dots blink. That should give me enough colors for the monsters, the walls, the doors and the items. Arrows for movement (first press turns, subsequent presses move in that direction), fire for shooting, and second fire for the inventory. Seems doable.
The monsters will be re-spawning (they are behind everything), but the items like ammunition and health packs will not — so you need to find the exit as fast as possible.