Gunnm/WMG

Battle Angel Alita is the future of:

• Both versions of Rollerball
• Terminator: James Cameron will find a way
• Repo! The Genetic Opera: A black-clad, otherwise mild-mannered guy doing dirty work (that he secretly enjoys) so his Ill Girl (for the moment) "daughter" doesn't have to while the rest of the Crapsack World is controlled by a kind of Mega Corp...
• The Amazing Screw On Head: Seen here, they've made screw-on heads to a science.
• Fist of the North Star: Panzer Kunst is descended/incorporated techniques from Hokuto Shinken. That's where moves like Herzschlag came from. The "meteorite" that fell is really a global nuclear war.

Battle Angel Alita is the past of:

• Battlestar Galactica: The remaining 10 copies of Alita/Gally/Gunnm are the ancestors of the Cylons via reverse engineering what little bits of them were left by Sechs.
• WALL-E: Kaos clearly lives in Wall-E's truck; the Venusians are from a Star Cruiser that never returned to Earth; the robots of Jeru are Obake-like counterparts of the Axiom robots.
• That racing-mecha anime on Cartoon Network
• Claymore: Den is clearly the ancestor of the Northern Awakened Being
• Firefly: Lotsa Waif Fu up in here.
• Tengen Toppa Gurren Lagann: Hell, why not
  • Well, Heroic Resolve does seem to allow people to do some pretty wacky things in Gunnm-land...the beginnings of Spiral Power use?
  • Zekka scores high on the "Romance" scale, and his compound eyes look a bit like a certain Crazy Awesome guy's shades...
    • Except they aren't eyes at all. These are just decorations, his real eyes are those three little bumps on his forehead.

The "Angel" of Mars is Alita's friend Erika from 200 years ago

The hair matches, and she's the only other person who knows Panzer Kunst (and can still use it). Alternatively, the "Angel" is Alita's brain in a body that looks like her friend, courtesy of Super Nova (it's a dick move and he'd totally do it) OR (and this is more likely) Mbadi's panzer kunst-master lackey in a similar body due to the fact that the last we see of Super Nova he'd claimed the lackey's squished head and was headed to Mars.