The first time I heard Paranoia Hades I got a strange sense of deja vu, or perhaps deja entendu, as it was the music that seemed familiar.  After a few more playthroughs I recognized the familiar bit: there were chunks of music that sounded like they came from Doom II.

I recently went back and replayed Doom II - yeah, I still have it, I'm an oldschool Doomer - and heard what I was looking for on the first map. (You can hear the music from that map, and all others at Paul's Stuff - he fed it all through his sound card, apparently.) Compare the melody of Map 1, Entryway starting at 0:19 and repeating at 2:23 with the melody in Paranoia Hades starting at 0:18 and repeating at 0:40 and 1:22.  (Maybe "melody" isn't the right word.  It's the part that you could actually hum, and which I imagine as being played on violins.)

I don't know if there is any intentional connection between these two pieces, but it seems awfully close.  Plus, Doom II is subtitled "H*ll on Earth," which would fit with Paranoia Hades.

I don't think there's supposed to be any connection. I mean, sure there's a tiny bit that sounds similar, but it's only 4 sequential pitches. Two people could have come up with the same thing.

It is really neat to hear that though! And I'm not saying there isn't a connection, just that there's no way to say for sure just by listening.

The artist of Paranoia Hades is jun, so you'd have to ask her. I know there was an artist comment on that song on the SuperNOVA 2 website, you should check it out.

Here are the comments about PARANOiA (HADES), from jun. 

http://www.konami.jp/bemani/ddr/na/gs/sn2/review/comment2.html

DDR SuperNOVA2 AC (Japan) -since HADES has not been unlocked for SN2 AC (US) yet-

http://www.konami.jp/bemani/ddr/jp/am/sn2/special/artist/artist04_d.html

Goodbye (^^)v 

P.S.: I think they just sound similar, too.

I wouldn't be surprised if the similarities were just a coincidence.  It's a pretty close coincidence, as it's not just the notes but the way theiy're played and their placement in relation to the other musical threads within the piece.  But there are always strange little coincidences out there.

Still, every time I dance that song I flash back to Doom II, and for me that's not a bad thing.  :)