The timeline completely changed. Because Trask was stopped from creating the Sentinels, X-Men 1, 2, 3, X-Men Origins: Wolverine and The Wolverine don't exist anymore.

Essentially it was a clever way to reboot the whole franchise.

You always have to ignore some shit to make it believable

I think he'll have his metal claws back, but they won't go into detail about it.

1. -He had bone claws for years in the comics when Magneto went crazy and tore the metal out of his body. They still cut stuff (I called bullshit!) because they were supposed to be super dense. Hey, just go with it. And I'm sure Wolverine still gets his claws. He doesn't remember anything after drowning. I bet all kinds of stuff still happened to him. Xavier wouldn't change too much with his knowledge of the future, would he?

2. Speedy Gonzales was too powerful. He would have finished the entire movie by himself. Just know he is Magneto's son and a version of him is now in the Avengers universe. He was in the cell with Magneto's other child at the end of Captain America: The Winter Soldier.

3. Time travel fixes everything.

4. Those cartoon sentinals were bitches. Even Jubilee was able to take one down. Killing a Sentinal is not fun. A single Sentinal is a huge threat. They did you a favor.

5. Did Stan Lee have a scene? I missed it, too! Also *spolier* Apocalypse. The X-Men are in serious shit if they make a movie with that guy--the "First Mutant" and his Four Horsemen.

6. Did young Xavier ever move stuff with his mind?

7. Yes. Mistique is pretty hot. I would do her.

They were mentioned occassionally in passing, iirc, in stuff like blueprints that were in the background of certain scenes.

(Edit: Apparently it was during a training session scene in The Last Stand that they appeared)

Jean may still go crazy in the new timeline, but it hasn't happened yet because they rebooted everything.

And OT: Yes, I agree.  This was by far and a way my favourite X-Men film.  It's probably my favourite superhero film in general to be honest.

I liked it as a comic fan, but by a cinema appreciation perspective, First Class is a better movie. As far as this one goes, the rhythm falls abruptly by the final section and, worst of all, young Magneto has little screen time and ridiculous lines and motivation. The only one that made him justice, as for what I had expected because of the previous flick, is the obvious Plane scene. I loved the Stadium levitation as any other Erick's fan, but at the same time it's not much different from the bridge scene from III, and they ruined everything by putting it on the trailer. Plus, his relation with Xavier, the highlight of First Class, is practically forgotten. A good, fun movie with great action, but not the best X motion picture. Maybe even the second one is better.

It was a pretty good movie.

I would place it third after First Class and X2, but it's a fine movie. Good action, interesting character development, and a fun sense of humor. I wish Stewart and McKellen had larger roles, but it's tough to juggle so many characters. The scene in the kitchen with Quicksilver was definitely a highlight :)

Fanboys have short attention spans and memory. It was good, but not that great, certainly not as great as X2.

The movie was very underwhelming in how it handled both the time travel and the characters.

My biggest issue was how Quicksilver was painfully underused. In fact, the second he left the picture, the pacing (ironic) just went downhill. 

Character motives also bring the writing into question. The entire 3rd act just felt rushed. Even the action was sub par. 

Overall it just didn't feel like a true sequel to first class or the original trilogy, even if it did blend to two fairly well. It just seemed like the existence of the movie is purely there to serve as a set up for X Men Apocalypse and the inevitable reboot. 

Honestly I would say it was the worst x/men yet. Me n my cousin saw it and we both thought it just sucked.

Opinions, how do they work?

I rewatched all 4 previous Xmen films before I went to see Days of Future Past.  I still preferred it to any of them (X2 came close, but I still didn't enjoy it as much).