Every Tuesday, I review the newest Blu-ray releases and let you know whether they’re worth buying, renting or skipping, along with a breakdown of the included extras. If you see something you like, click on the cover art to purchase the Blu-ray from Amazon, and be sure to share each week’s column on Facebook and Twitter with your friends.

WHAT: After retrieving Loki’s scepter from Hydra, Tony Stark (Robert Downey Jr.) and Bruce Banner (Mark Ruffalo) attempt to use its power to produce an army of A.I. robots that can protect the world from any threat. But instead, they create Ultron (James Spader), a maniacal robot hell-bent on destroying the Avengers and remaking the world in his image with the help of a pair of super-powered twins (Aaron Taylor-Johnson and Elizabeth Olsen) who have a personal grudge against Stark.

WHY: The first “Avengers” was so much fun that it didn’t seem possible that “Age of Ultron” could be a disappointment, and yet it’s hard not to feel somewhat unsatisfied by the final product. Though it’s a decidedly darker and grittier entry that gives its characters actual problems to deal with, some are more successful than others. It makes sense that the three Avengers who have yet to receive their own solo movies – Hawkeye, Black Widow and Bruce Banner/Hulk – are treated the best in terms of development, but it comes at the cost of other characters, particularly Thor, who gets saddled with a pointless subplot involving the Infinity Stones. Newcomers Quicksilver and Scarlet Witch are also given little time to make an impression, and though James Spader is perfectly cast as Ultron, the robot isn’t a very engaging villain. The buffet of characters can be a tad overwhelming, but director Joss Whedon juggles the large ensemble and overstuffed action scenes incredibly well, creating memorable moments within each sequence that are filled with classic Whedon banter. In fact, while it’s arguably one of the studio’s weaker entries to date, “Age of Ultron” is still a mostly enjoyable installment that sets the stage for the future of the Marvel Cinematic Universe. With that said, I don’t envy the task ahead for the Russo brothers, because if this film proves anything, it’s that the upcoming two-part finale is going to be an even more daunting proposition than it originally appeared.

EXTRAS: In addition to an audio commentary by writer/director Joss Whedon, there are four featurettes – covering production, location shooting around the globe, the Marvel Cinematic Universe and the Infinity Stones – as well as deleted scenes and a gag reel.

FINAL VERDICT: RENT

WHAT: Freshly divorced and raring to get back to work, Vincent Chase (Adrian Grenier) agrees to star in Ari Gold’s (Jeremy Piven) first movie as studio head under one condition: he also wants to direct it. But when the film goes over budget and Vince asks for more money, the financier’s son (Haley Joel Osment) begins to interfere with the production, pushing Ari to the breaking point as he tries to protect Vince’s vision and his job.

WHY: “Entourage” has always operated as a larger-than-life helping of male wish fulfillment, but while creator Doug Ellin was no doubt seduced by the lure of going even bigger for the film version, it’s refreshing to see that, for the most part, the movie is just more of the same. It’s like a supersized episode of the HBO show, not to mention a welcome return to the lighter, more playful tone of the earlier years that made it so popular. Admittedly, the movie doesn’t hit as many high notes as the series delivered at its very best, but fans of the show will like it regardless, and it might even convince some non-fans to go back and watch it from the start. More than anything else, though, “Entourage” is a fitting farewell to a series that never really felt like it got the ending it deserved, and Ellin embraces that second chance with so much fan service that it occasionally gets in the way of the story. The movie tries too hard to please everyone, resulting in a messy narrative, but it’s also sensationalized, fizzy fun, and as fans of the TV series know only too well, that’s all that counts.

EXTRAS: There’s a making-of featurette, a roundtable discussion with writer/director Doug Ellin and the cast, a behind-the-scenes look at Vincent Chase’s movie-within-the-movie, some deleted scenes and a gag reel.

FINAL VERDICT: RENT

WHAT: The Bowen family moves into a new home in the suburbs, only to discover that it’s haunted by evil forces when their youngest daughter is taken captive by the ghosts. Desperate to rescue her from purgatory before she’s lost forever, they enlist the help of a paranormal investigator (Jared Harris) who specializes in poltergeists.

WHY: Tobe Hooper’s “Poltergeist” may not be sacred ground (no pun intended), but it’s enough of a cult classic that the only reason to bother remaking the film would be to improve upon what already exists. Unfortunately, director Gil Kenan’s remake is so passively mediocre in just about every way that it’s not so much an affront against the 1982 original as it is a giant waste of time. The whole thing feels rushed, with absolutely no buildup or tension, and save for one scene where the kids are terrorized by the poltergeist, very few scares as well. Sam Rockwell and Rosemarie DeWitt are also horribly underused in the parent roles, although the former at least tries to make the best of the paper-thin script by injecting some humor into the proceedings. Jared Harris’ ghost hunter is one of the few updates that actually make sense, but it’s a worn-out plot device that’s been better utilized in recent horror films like “Insidious” and “The Conjuring.” “Poltergeist” certainly had the potential to be much better, which is perhaps why it’s so disappointing that the movie doesn’t even seem like it’s trying.

EXTRAS: There’s an alternate ending and a photo gallery.

FINAL VERDICT: SKIP

WHAT: Set in rural Colorado, a pair of 10-year-old boys (James Freedson-Jackson and Hays Wellford) discover an abandoned cop car in the woods and decide to take it for a joy ride. But unbeknownst to them, there’s a body in trunk that connects the vehicle’s owner – the corrupt Sheriff Kretzer (Kevin Bacon) – to some very bad deeds, and he’ll do whatever it takes to get it back.

WHY: Though Jon Watts was recently handed the keys to Sony’s Spider-Man franchise, he probably wouldn’t have even been on the studio’s radar were it not for this Sundance hit. Though “Cop Car” doesn’t quite rival the classic Coen brothers crime thrillers that clearly influenced it, Watts’ ability to wring suspense out of the simplest moments goes a long way in making the film a lot more engaging than you’d expect. “Cop Car” is unlike traditional neo-noirs in that it flips the script by centering on two innocent kids instead of the typical, morally gray protagonist, like if the gang from “Stand by Me” had discovered Anton Chigurh’s briefcase of money and kept it for themselves. The child actors do a decent job with the material, and they grow on you over the course of the movie’s lean, 88-minute runtime, but it’s Kevin Bacon’s turn as the wiry, coyote-like sheriff that holds your interest beyond the intriguing premise. While “Cop Car” isn’t totally convincing in its use of violence to reflect the boys’ loss of innocence, it’s a solid, low-budget thriller that proves you don’t need to spend a boatload of money to make a good film.

EXTRAS: There’s a making-of featurette, but that’s all.

FINAL VERDICT: RENT