There are no enemies or rupees, and your exploration is very, very limited.
The legend of Zelda (Gameboy)
This is an fan demake of the legend of Zelda made in GB studio.
You move with the arrow keys and interact with things with Z. After getting the sword swing it with X (there are no enemies so it's just for aesthetics). Bring up the map with ENTER and also use it for START. See how many rupees you have with SHIFT.