The original release of this game came with an anthology booklet.
Mega Man 8, besides the first Mega Man game and Mega Man & Bass, is about the only other game to feature Wily Robot designs from Capcom. Tengu Man and Astro Man were Capcom creations; everyone else was submitted via Robot Design contests.
Mega Man 8 almost wasn't released in the U.S., due to Sony saying it "wasn't 3D enough". Capcom nearly had to fight them to get the game released in the U.S., but thankfully Sony granted them the approval to release it.
Although they weren't in the PlayStation version of Mega Man 8, if you play the Saturn version of this game, you'll run into two old foes making cameo appearances, and even going to fight you again! Who are these two foes? None other than Cut Man (from Mega Man 1) and Wood Man (from MM2)! Cut Man appears in the intermission stage after you beat the first four Wily Robots, and Wood Man appears as a mini-boss in Seach Man's stage.
The opening and ending songs were altered from the Japanese version of the game. The opening song in the Japanese version was a song called "Electric Communication" from J-Pop group Ganasia, and the ending theme was another song from the band, called "Brand New Way". Both songs are actually quite a lot better than the slightly bland instrumentals that played in the opening and ending of the U.S. and European versions.