Resident Evil 4 on the GameCube is progressive scan, but letterboxed and not true 16x9 widescreen.
The game screen fits on a full screen display with black bars on top and bottom, so on a widescreen set, use the zoom 1 function to fill up the entire widescreen. Because it's not native 16x9 widescreen, there are obvious jaggies. Can't complain though, the game still looks and plays great! If it appeared on original Xbox, it would shadow the current Gen material.