Underworld (film)/YMMV

Base Breaker: Rise of the Lycans. Some fans hated the film as, due to its nature as a prequel, the story shifted away from that of the romance between Selene and Michael. Some fans enjoyed the film precisely because of this.
Designated Villain: Lucian, oh so much.
Fridge Logic: The nature of blood-bourne disease that creates "immortals" is somewhat contradictory:

1. Selene is exposed to Michael's lycanthropy-infested body fluids, but does not become a hybrid herself, yet when she drinks the blood of Alexander Corvinus, she becomes immune to sunlight.
2. William Corvinus attacked and killed numerous vampires with his claws and teeth, consuming their body fluids, but never becomes a hybrid.
3. Markus Corvinus seems to gain the memories of any creature whose blood he drinks, in any amount and in any situation, yet no other character does so. Lucian bites Michael and implants his memories, but the only other case of "transmitting" memories was when Selene awakened Victor.

- It's more than Markus. Selene explains that only elders have the ability to properly arrange their memories into a coherent history. It's what she was attempting to do when she awakened Viktor, with less than perfect results, and in general, it's implied to be the way the elders manage to maintain consistent rule, despite their two hundred year bouts of hibernation. Michael's fragmented memories from Lucian are more likely a side effect of being turned rather than anything to do with blood, as seems to be the case with vampires.
  - And as for the rest, we could probably mark it down to "the Corvinus bloodline is weird and not all of the rules apply" since Markus and William are the progenitors of vampires and werewolves, respectively, and Alexander, as their father, probably shares at least some of the traits.
- And on a separate note, from the beginning, it was stated that Vampires and Lycans are both biologically compatible, and capable of breeding. In six centuries or more, why didn't Lucien just capture a female vampire, and get her pregnant? Or, just in more recent times, use artificial insemination? Hell, if he was squicked over the idea of rape, he could have used vampire blood on a volunteer. Instant surrogate mother.
- Marcus apparently gets a chance to kill all of the children he doesn't want every two centuries, with the only people close to strong enough to fight him lying in torpor. And, by vampire tradition, also completely dependent on him for reawakening.
- By rights, the 'blood borne disease' thing that makes vampire/werewolf hybrids impossible should be lethal to both biter and bitten.
- Viktor's internal Masquerade is dependent on very powerful Markus not getting cranky during his 100 year rule segments. While Viktor has taken care of the key to William's prison fairly well, that does not go for Markus deciding to shatter everything else.
  - When Markus finally does go ballistic, his father Alexander barely raises an eyebrow.
  - He was likely biding his time. Viktor was the only one that had any knowledge of the key or the location of the dungeon. Remember, Lucian's escape occurs during Viktor's reign, which wiped out a significant part of the vampire population - or at least those related to the high council. Markus would have awakened two hundred years later to find himself dealing with an entirely different coven loyal to Viktor and Amelia. It wasn't until Markus became a hybrid that he was was physically powerful enough to take out the entire coven himself. Regardless of the events of the first movie, things were bound to come to a head soon. With modern technology and biological science at his disposal, Viktor would have eventually come to realize that Markus's insinuation of supernatural heritage was a deception that no longer had to be entertained.
Ham and Cheese: Bill Nighy is actually a good actor. Viktor, however, is the hammiest character in an extremely hammy franchise.
Mary Sue: Selene, oh-so-much. Being the director's wife, her character received the full "DM's Girlfriend" treatment and gets to get all the superpowers, have everything revolve around her, and on and on. It's at least as bad as the Resident Evil film series about this.
Moment of Awesome - When Viktor heads off to kill the 'Abomination', Michael, the newly transformed hybrid emerges, and as Viktor and he stare each other down, Michael SHOVES Viktor, sending him flying back.
Moral Event Horizon: Viktor allowing his own daughter to be murdered for consorting with Lucian in the third film. It's so monstrous, nobody that has seen any other film will be able to know whether to root for the vampires or the Lycans after that.
Narm: "You betrayed me! To be with an A-NI-MAL!"
Nightmare Fuel:
- What the villains in Awakening planned to do to Eve.
- Shown earlier, in Rise of the Lycans, during the outbreak of the Lycan slaves. Where some of those rather large ballista bolts landed could be a little on the squick side for some.
Romantic Plot Tumour: Aside from a physical attraction and the fact that everyone is trying to kill them, what exactly do Michael and Selene actually have in common?
Schrödinger's Gun - Remember that amulet around Lucian's neck in the first film? It wasn't until Evolution when we realised it was the key to William's prison.
So Bad It's Good / So Cool Its Awesome: Your opinion of the films is probably one or the other, if you kept watching after the first one.
Tear Jerker: The death of Sonja is surprisingly touching.
- Lucian's retelling of Sonja's death to Michael is also very sad, and really makes you feel for the guy.
The Woobie: Lucian, at the end of Rise of the Lycans.