https://archive.today/AUMXKIGN reports that the game runs at a resolution of 1328x1080, rather than the 1920x1080 resolution that is better known as 1080p. This is because, like Halo: Combat Evolved Anniversary on Xbox 360, the campaign offers two graphics and sound modes that you can switch between on the fly: original and enhanced. Running two graphics and sound engines at the same time "put a hit on resolution," according to 343 executive producer Day Ayoub. And although he claims Halo 2 Anniversary "looked fantastic" at even 720p, work has been done to bump that up--just not quite to 1080p.
"So in the last weeks of development, our teams were able to meet a stretch goal and the campaign of Halo 2 Anniversary now runs 60 fps at a crisp resolution of 1328x1080," Ayoub said, "which is a significant and meaningful boost in image quality we think fans are really going to appreciate."
1328x1080
Wow it's like I'm really playing Killzone.
I sure do love all these True Full HD™ IMAX™ Experience games in the Next Gen™.