The last Ghost Rider movie established Ghost Rider's origin. Johnny Blaze is possessed by a demon and, as such, is Ghost Rider. Spirit of Vengeance accepts this basic fact and goes from there. With the exception of this, the first movie isn't referenced.
Nicolas Cage reprises his role as Johnny Blaze in Ghost Rider: Spirit of Vengeance. Since we last saw our dark hero, he had grown to despise his powers and the ways in which he is compelled to use them. To avoid hurting people who don't deserve it (well, maybe just a little), he relocates to a remote location and tries to be as much of a hermit as he can, while trying to learn to control the demon within himself.
Blaze is not to remain in his seclusion, however; it turns out there is a rare astronomical occurrence which provides a window of time during which the devil (Ciaran Hinds) can transfer the spirit from his weakening, aging human form into a younger, stronger body. Moreau (Idris Elba), a black, French, alcoholic priest and an operative for some clandestine religious organization seeks out Blaze to use him to find this poor, unfortunate young man serving as the devil's intended vessel. He promises Blaze that if he can bring him the child for protection, Johnny Blaze can be made rid of his demon... a chance to be rid of the Rider.
Blaze/Ghost Rider joins forces with Moreau and Nadya (Violante Placido), the mother of, Danny (Fergus Riordan), the aforementioned young man/future home of the devil, in an attempt to prevent the devil from performing the transfer ceremony and becoming unstoppable. Johnny Blaze will have to secure the child if he hopes to rid himself of his inner demons, but if he succeeds, he will be powerless to protect him. The devil needs someone to procure Danny for him and he's already employing Nadya's ex-boyfriend, Ray Carrigan(Johnny Whitworth), so after upgrading Carrigan into a supernatural being with the power to envelop his enemies in darkness and a touch that brings rot and decay to anything he touches known as BlackOut, he sends him after the boy.
The story aside, the direction is different in Ghost Rider: Spirit of Vengeance. The feel, if you will, is more light-hearted. This movie isn't taking itself as seriously as the first one... but that's not a bad thing. There are a couple (awesome) scenes in which Ghost Rider takes over some vehicles other than his motorcycle, corrupting and transforming these vehicles into hellish, monstrous versions of themselves. With the discovery that the spirit inside him is, in fact, insane, we are treated to some comical scenes in which Johnny Blaze is trying to fight against the change into the Rider and goes through various partial transformations and back, as he resists. These changes are heavy CG elements in the film, but, while comical in nature, look pretty good.
In fact, the special effects in Spirit of Vengeance are really well done, from the charred look of Ghost Rider's skull to the flame effects to the really nice touch of the bubbling leather on Ghost Rider's motorcycle jacket. While these CG elements look more gritty and realistic, one reason for the more realistic feel of Spirit of Vengeance is due to the number of things that were actually done with practicals. Scenes where Ghost Rider's motorcycle rides up for him to get on aren't done fully in CG; there's merely some cleanup to visually remove the stunt man who is riding the motorcycle while hanging off the other side. In one scene, when Moreau has a spill and goes careening off a cliff, the scene is actually filmed with a camera man and the stunt man both in flying harnesses, hanging over the cliff from a crane. Insane stuff.
If you're into movie-making magic and methods, you should definitely check out the special features. The Path to Vengeance offers a glimpse on how the movie came about, from creating the script to filming, post-processing, audience testing, showing it off at Comic Con and, finally, releasing the film. However, the Directors' Expanded Video Commentary actually shows more about the making of than The Path To Vengeance. The commentary has the two directors of Ghost Rider 2 talking about how the movie was made, why certain scenes came about and how certain effects were achieved, but instead of simply talking over the movie, the commentary will display Mark Neveldine and Brian Taylor talking in the foreground with the movie playing behind them in an inset window, sometimes with an additional display layered on top, displaying the raw footage so you can compare the original to the final cut. At certain points, they pause the movie altogether to discuss some particular aspect in finer detail. Personally, I'm not usually a fan of commentary; it usually seems to detract from the film itself. In this commentary, however, they're not constrained by the amount of time that a scene is onscreen and they can discuss what they are passionate about, so it comes off like a feature-length making-of, rather than directors pretending to be on Mystery Science Theater 3000.
Ghost Rider: Spirit of Vengeance is not the most amazing Marvel movie, but I enjoyed watching it - and actually enjoyed watching the commentary, as well. This one wasn't a must-see-in-theaters sort of movie, but it definitely seems worth adding to your Marvel movie collection, if you have one. And, if you do get it, you'll want to pick up the Blu-ray version, since the cool special features are Blu-ray exclusives.