Ravel's guitar

Ravel's guitar is such an imitation of the devil arm Nevan from Devil May Cry 3. Not only are they purple guitar weapons, but they're also lightning elemental and capable of shooting projectiles over a distance. That move is so cheap!!

Reaction attack - Stinger

This move has absolutely nothing do with Devil May Cry... except for the name. Devil May Cry's signature attack is called Stinger, and no DMC fan who plays Godhand can possibly not go "Ah! It's STINGER!" :P

GOD TRACKS - Track #8 (Devil May Sly)

.... Do I need to explain?

Rocket launcher

I know I know... Rocket Launchers are everywhere. But come on, don't tell me you didn't think "Resident Evil!" when you first saw it appear out of a box in the middle of nowhere in Godhand??? NO?? SERIOUS??? Damn...

Spiked Demon

It didn't strike out to me at first/immediately when I saw the spiked demons, but when someone reminded me that they are similar to Resident Evil 4's notorious Iron Maidens... I agreed. =) Of course, other than the spikes and the fact that they're 'not human', Iron Maidens and spiked demons are different, especially in speed.

Amaterasu

Just one of the many red chihuahuas in the chihuahua race... named after the white wolf in Okami.

Elvis's line

Spoilers: In the cutscene before you fight Elvis for the 3rd time, he says "Say hello to Viewtiful Elvis, HENSHIN!" The only thing he's missing to complete that line is "A-go-go-baby!". :P

Mad Midget Five

Thank god Joe does not look like these douchebags... though these douchebags still look like him. o_o... Also, it is said that they are a tribute to the 'Handsome' characters of Killer 7, a game also made by Shinji Mikami.

Viewtiful Pup

Just one of the many purple chihuahuas in the chihuahua race...

Mach Jab

It's just the word "Mach" really... >_>

Dragon Punch (Shoryuken)

Anyone who's played/seen/grew up with Street Fighter would know this in one-tenth of a glance.