Take three comedic actors who have driven their onscreen personas into the ground, a director whose previous comedy was one of the least successful at the box office in recent memory, add some aliens and what do you get? Well, a mess, and thankfully The Watch somehow works far better than it has any right to. Sure, Ben Stiller’s grating perfectionist protagonist is as irritating as ever, Vince Vaughn’s rants are landing less frequently every time he opens his motormouth these days, and the Seth Rogen/Evan Goldberg script has more dick jokes crammed into 90 minutes than Kevin Smith’s entire career. It’s a shaggy movie filled with holes and flaws, but it’s also pretty fun, with a far better sense of the horror/sci-fi elements than any of the marketing suggested and there’s enough talented people involved to keep the laughs coming at a respectable rate. Maybe it’s a case of subterranean expectations being rewarded by unexpected competence, but this thing seemed to play shockingly well.

Ben Stiller stars as one of his typical underachieving type-A personalities. In this case, he plays a Costco manager always on the look out to start a new club where he can boss people around. He gets a chance when the night security guard at Costco is killed and skinned. So he does what any rational person would do and starts up a neighborhood watch to catch the killer since the local police are led by Will Forte and are therefore hilariously useless. He soon teams up with a quiet mama’s boy/closet psycho played by Jonah Hill, an oddball nerd played by Darkplace comedy genius Richard Ayoade, and Vince Vaughn, you know, being Vince Vaughn. They start working the streets a bit, but mostly become beer buddies until one night they discover that their small town infested by aliens of the outer space variety. Well, these suburbanites are going to have to kick some scaly scum all the way back to Mars, right? If only there was an obvious target, like say that creepy neighbor suspiciously played by Billy Crudup? Oh and do you think Stiller will finally be able to get his wife (the always lovely Rosemarie DeWitt) pregnant? Hmmm, well I’ll bet all the questions will be answered. It’s not really the type of movie that relies on ambiguity, now is it?

Sounds dumb, right? Well, it is. But at its best, pretty damn great dumb fun. The foursome at the center of all the madness are clearly improvising up a storm throughout, and while that can often lead to dead ends that seem to only amuse the performers, it also led to gold plenty of times. Vaughn spins some verbal diarrhea that stops stinking once the film starts taking his character seriously (particularly whenever going after his daughter’s new boyfriend), Stiller shoehorns in a few awkward comedy gems (especially when discussing the inner workings of Costco), and Hill provides a broader variation on his creepy man/boy from Cyrus. The hit-to-miss joke ratio isn’t as high as it can be for any of those guys at their prime, but they collectively they pull down more than enough laughs for a Hollywood comedy. They are also helped immeasurably by Ayoade whose oddball sense of timing has been a secret kept by the Brits of too long, and Will Forte who as far as I can tell is capable of making anything funny at least for a few minutes. The cast is quite strong overall with small roles from the likes of DeWitt, Crudup, and R. Lee Ermy providing some more grounded comedic work to curb all of the improvised lunacy.

The Watch comes from director Akiva Schaffer, best know as the tall guy from The Loney Island who sings the least and directs the most, as well as the guy behind the quite underrated Hot Rod. Schaffer’s got a strong enough comedic sensibility to keep the main players in check and he’s also one of those rare comedy directors who actually cares about how a movie looks, which is pretty damn important for this type of cross-genre flick. To be honest, he’s better at parodying movie styles than nailing them earnestly, with scenes like when the gang posses with an alien corpse before it comes to life playing far better than the few times he goes for actual suspense and scares.

The straight genre material thankfully only occurs early on and briefly, so it’s not that bad, and any stylistic bumbling behind the camera is instantly made up for by the fact that the alien is actually played by a guy (specifically Doug Jones, best known for playing almost every Guillermo Del Toro monsters) in an amazing animatronic suit that’s infinitely more impressive than any CGI (there’s still plenty of that, but the effects are mostly refreshingly practical). Considering all the different directions that this movie tries to spiral off to at once, Schaffer does an admirable job of holding it together as well as what was most likely the unenviable task of juggling all the superstar egos on set.

There are certainly plenty of problems with the movie though. Subplots involving Stiller’s infertility and Vaughn’s promiscuous daughter often feel like leftovers from a early boring draft of the script by Jared “Mr. Popper’s Penguins” Stern, and while the Rogen/Goldberg rewrite clearly helped increase the laugh count, it often feels like the two stoners/writing partners were more concerned with breaking the record for most dick jokes in a feature film than fixing the structural problems of the script. Fortunately, this leaky vessel mostly holds together thanks to the cast, director, and impressive effects (those are the key ingredients of a sci-fi comedy after all). At it’s best, The Watch recalls some great suburban paranoia dark comedy/horror films like The ‘burbs and Society. At it’s worst the movie feels like a new manchild Judd Apatow joint + aliens – emotional investment. Either way, it’s entertaining (and surprisingly a hard-R) genre comedy.