Gee, I wonder why. Also wonder why it's only Megaman 1-6 when the anniversay edition that came out back in 2004 had Megaman 1-8 and the power battles. -_-
Likely only 1-6 because they were previously released on the PS1 so it's probably an easier conversion. 7 and 8 woulda been emulated but 1-6 were remastered so it's probably easier to upgrade to HD