not so much plot points, but just scenes that COULD be taken out without the story line going astray.
Several close ups of vaginal penetration...
a montage of the girls who are screwing ozaki.
you actually see a close up of nagumo masturbating outside the girls locker room.
before nagumi confronts nagumo and akemi for the first time on their first date, she's actually sitting back and enjoying the show, masturbating herself.
several shots of vaginal penetration when the female nurse is being screwed by the transformed nagumo.
it starts off with a recap of what happened in the first episode.
Where, in the movie, we see a "flashback" of amano confronting Sui Kakaju in the tour. This is the first scene of the second episode, not a mere flash back. But it mainly shows more destruction of Tokyo and of course, more sex and vaginal penetration between Sui Kakaju and the female sacrifice. So not much is lost to be honest.
When Nagumo and Akemi first meet Kuroko, while Nagumo is asking if Akemi believes that he doesnt know the woman from the other night, Amano actually states that the woman is in fact, Nagumi, his sister (this isnt stated in the movie).
When they first meet Megumi, she is in mater of face, being penetrated by a "demon punk from the demon relm" at their school... you know, the whole floating in mid air while what looks like a crustacean is being inserted into her vaginal . And the funny thing is, the just sit back and watch it all... well, Akemi is crying in fear into Nagumo's shoulder... And then Megumi vaporizes the "demon punk" in a fury of a climax, only to have Megumi proclaim "ah, i haven't come like that in a long time." and Amano asking if her standards have dropped.
The next scene is where Nikki is in the dark room with the other females, this in fact, is an extended lesbian tryst amongst all the females. While they 69 each other, among other acts, they laugh about Nikki the "dickless wonder". Then comes the massive death scene of all the naked females. Though, i think the whole scene where the two demon's talk to Sui Kakaju about Nikki hating Nagumo and he being the perfect candidate was cut.
You actually find out why Nikki is getting his guts kicked in by his father. Simple. He stole from his fathers wallet.
There is a bit of an extended scene where Nikki, knife poised over his unwrapped fallus has all the voices of the hours before going through his head...
The next scene is an extended scene of Amano and Co. flying to the demon realm. Nagumo is flying due to Koroko's placing right under Nagumo's crotch, which totally make this scene worth it. Nagumo scolds Koroko for not going fast enough, and Koroko being the little prick that he is, lets Nagumo fall, only to be helped by Magumi. Nagumo thanks Magumi, and he REALLY means it as he has a under-skirt view of Magumi...
The next scene has been extended a tad, in my opinion. Amano is talking about the edifice that has been built and the inscription about "a big yahoo called the Overfiend" who comes back every 3000 years. and how The Great Elder will see if he really is the Overfiend.
After Nikki fights the gang (which remains unchanged in this version) Nikki brings back the three girls to where they are at. This scene contains scene of the girls sucking on Nikki's demon lollypop, two girl, one licking out the other, whilst Nikki sculls the receiver of the other females tongue. mainly just some sex scenes that wouldn't change the story if they took them out.
But yes, you are correct, there is a scene (the same scene, in fact) where Nikki's penis "rots" much to Nikki's pain. The demon's then pop up on the multiple screen's where they assure him not too worry, but there are a couple of things that he needs to do. This, in fact, explains why nikki gobbles down Nagumo's sperm and blood in later scenes, thus "making the world his own"
Then it comes to the akemi/negumo love scene. a couple of vagina shots, and a close up of Akemi gobbling his Fallus whilst Magumi is outside masturbating to the two of them, not much is different in this immediate scene. When Nikki comes into it though, it has changed. He eats Nagumo's man chowder and then his demon Fallus grows, the manhood doing his Fallus good, and rejuvenating it to its previous state.
After a brief scene with the demon who handed nikki the demon fallus dying at the hands of Amano, and then flying off with Sui Kakaju in tow, the next scene that follows is of Nagumo visiting Nikki's home, only to be confronted with the two bodies of nikki's parents and the other demon, this scene has been extended, with a montage of clips from the previous episode where Nagumo changed into the Overfiend, after the second demon confronts him about Nagumo also being as much of a murderer as Nikki. Nagumo starts to transform in this scene, his eyes glow blood red, the demon gets scared... Nagumo's chest starts to ripple, and a tentacle made of heads bursts out and obviously kills the demon.
Cutting back to the trailing of Amano by Sui Kakaju. Sui ends up impaling Amano, then tells him about how they need another person from the same realm to kill Nagumo, then it cuts to the construction site where Nikki is molesting Akemi. Nagumo comes into the scene, ended up getting totally done by all the falling metal struts, then it cuts back to the Amano/Kakaju fight.
The main deal with this scene is that they have interlaced the scenes together, cutting back and forth. Though they remain largely unchanged, except for a scene where nikki is molesting Akemi with his tongue and demon fallus after Nagumo is supposedly killed. He comes to the realization that Akemi was the only one that was ever nice to her, cue nagumo coming back from the dead scene.
After Kakaju dies, he summons one of his female friends, and then one of his horns falls off and then he dies, this explains what was shoved down Niki's throat after he dies himself.
The second episode ends when Amano is sent back in time after he tries entering the protected castle.
a normal recap of the previous episodes proceeds the third episode, talking about how nikki and nagumo fell in love with the same girl, how the man-beasts love the overfiend and the demons fear it. How Nikki sold his soul (i never knew a man's soul was his Fallus, strange, i know) etc. etc. etc.
The episode begins with a rehash of the last scene in episode two, where Amano is sent into the future, then when the episode actually begins, it begins with a literal threesome, Kakaju and two other female's begin to make out, its quite amusing. For the fact that he wants their bodies, they start to have an orgy of sorts. some vaginal fingering follows. as Kakaju transforms from Nikki's body, he suspends his lover up with tenticles and begins to pound them until he climax's then they both are destroyed (the females).
In the movie version, when Akemi is racing around looking for Nagumo, she passes two people, they are obviously making out because if two bodies are that close in Urotsukidoji, it can only mean one thing, they've got their tongues in each other's mouths and the male has his fingers down her tighty whities. But in the movie version, they dont show the male fingering the female, in the Perfect Collection, they do. Ala Photoshop!
In the proceeding scene where nagumo and akemi are having sex after she coaks him out of the closet (could this be some deep symbolegy that he has finally come out of the closet about his alter ego?) not much is different in this scene, a couple of vaginal penetration shots, here and there, all shots somewhat obscured by as blue tint, possibly because it wasnt a 100 foot long Fallus tentacle (seriously, they have some wacky moral issues over in Japan, i swear.)
in another scene, Amano is in the body of the Negumo, and this is a extended scene, Amano has a conversation with the True Overfiend, and he learns of the real deal, how the worlds came about, and what is going to happen to them.
thats all the real differences.
A very detailed comparison between both versions with pictures can be found here.