When it comes time to unveil number three, having two wholly unique and altogether great comedies on a resumé is a double-edged sword. For the subversive British duo of Simon Pegg and Nick Frost, the positive side of the blade is one to praise. Along with their “mate,” and director, Edgar Wright, England’s modern-day answer to Abbott & Costello took the genre community by storm in 2004 with the very sharp horror spoof Shaun Of The Dead, a film charged up with intelligent irreverence and undeniable panache. The chemistry between Pegg and Frost elevated in 2007’s buddy cop send-up Hot Fuzz, also directed by Wright and even more unique in its presentation and humor.

They’d earned the trust of film buffs worldwide, so when talk of Pegg and Frost’s next collaboration, Paul, first began, optimism was rampant. Then word came that Wright was off this one—to film last year’s Scott Pilgrim Vs. The World, a film Frost told us is "one of the fucking greatest films ever made"—and director Greg Mottola was in tow.

Mottola’s two previous films, the beloved Superbad and the poorly marketed but entirely recommendable Adventureland, proved that the guy has considerable skills, adding to the fanboy excitement surrounding Paul. As the cast built up with names like Seth Rogen, Jason Bateman, Kristen Wiig, and Sigourney Weaver, and details about the plot trickled about online, the anticipation couldn’t have been higher within the savviest of movie head circles.

Which leads us to the negative side of that sword: a bar set too high for the stars’ own good. Without Wright’s flashy and singular directorial style, Paul is more conventional than Pegg and Frost’s prior flicks, thus depleting its overall impact. Though, the softer blows aren’t killers. In fact, Mottola’s quieter approach complements the premise—about a CGI-rendered, wisecracking alien (voiced by Rogen) that smokes cigarettes, guzzles beer, and curses like Andrew Dice Clay—quite well here.

The computer-generated Paul is wonderfully executed, devoid of any overtly shoddy details or Atari-level graphics; it’s smart to fall back from dizzying edits and just let Paul live. The major problem with Paul the movie is that it’s just not all that hilarious. Not even when compared to the superior Shaun Of The Dead and Hot Fuzz—this sci-fi romp isn’t even the funniest movie of 2011’s first quarter (that honor goes to Cedar Rapids).

Unexceptional Pegg and Frost are still more enjoyable than most Hollywood comedy, though. And, for fans of science fiction, Paul is an enthusiastic high-five—with hands forming the Vulcan symbol, of course. Within the first five minutes, the geek-friendly tone is established. Graeme (Pegg), a comic book illustrator, and Clive (Frost), a middling sci-fi writer, are first shown inside Comic-Con, ogling chicks in Princess Leia costumes and stuttering in disbelief in the presence of their favorite sci-fi author (Arrested Development’s Jeffrey Tambor).

It’s the England natives’ first time in America, so they follow up Comic-Con with a tour of the country’s most notorious UFO sights in their Winnebago. Little time is wasted before they befriend Paul, a little green dude who’s been stranded on planet Earth for over 60 years. Paul quickly turns their duo into a trio, which helps the alien since he’s on the run from a pair of bumbling government agents (Bill Hader and Joe Lo Truglio) and one of their higher-ups (Bateman).

Paul’s best bits come from the interplay between Pegg, Frost, and voice-only Rogen. In long khaki shorts and comfy sandals, Paul is basically that droll smartass slacker who lived in your college dorm room and sat around puffing marijuana cigarettes instead of attending class. Rogen’s gruff pitch and hearty laugh suit the character well, giving Paul a consistently funny bent that’s aided by the on-point special effects. Frost, meanwhile, gets to play more of a full-fledged protagonist here than in his two previous collabos with Pegg, in which he played an underachieving doofus sidekick and an inexperienced but amibitious sidekick, respectively. In Paul, he’s given as much heavy lifting to do as Pegg, and both score.

The same can’t be said for Paul’s peripheral characters. Much of the film’s disconnect can be attributed to the uneven support team, which is not less the fault of the actors than the script’s co-writers, Pegg and Frost.

The deeper Paul moves into its running time, the stranger the characters arcs become for Hader and Wiig, specifically. Frequent Rogen collaborator Hader goes from a goofy law enforcer to a sadistic villain for no clearly defined reason, other than a vague sense of professional overzealousness. Considering that Mottola and company devote so much time to the Hader/Lo Truglio/Bateman subplot, Hader’s inexplicable descent into an evil cipher is hard to ignore.

Filling the token “love interest” slot, Saturday Night Live standout Wiig has a similar dilemma. Her character—Ruth, a devoutly Catholic lady who runs a Winnebago park and joins the two humans and alien on their adventure—is a missed opportunity for Pegg and Frost to generate profane laughs. After Paul zaps her brain, Ruth says her first dirty word and starts dropping cusses in every sentence, but the joke quickly runs its course, leaving Wiig with little to do other than take away screen time from Paul and his two best human buds.

Just when it seems like Paul is about to drown beneath its lesser characters and wavering strength, however, the film accelerates into an action-packed chase movie for its finale, and things really pick up. Dialogue winks toward sci-fi classics like Aliens and Back To The Future are solidly timed. An open terrain run-in with a massive spaceship recalls the climax of Steven Spielberg’s Close Encounters Of The Third Kind and hits the right notes of physical comedy and visual spectacle. And, most unexpectedly, the movie aims for emotional resonance and triumphs, drawing Paul’s time with Graeme and Clive to a close in a grandiose, and even touching, fashion. You’ll laugh, and you might even cry a little, though Paul himself would most likely diss you for that.

In the end, Paul wants to be an older and significantly rougher E.T. Is it victorious in that quest? Not quite, since it’s hard to imagine “Am I harvesting farts?” becoming the new “Phone home.” Knowing what Pegg and Frost are truly capable of, it’s only natural to feel a slight bit underwhelmed by this B-level product from the Brits. But for a harmlessly fun, at times creative, and thoroughly live-wired time at the movies, Paul is still a good call.