It’s been an interesting gestation period for Manchester, England’s The 1975.

The group, who has been performing together for 10 years, has released music as multiple bands since 2004 but it’s nearly impossible to find online. Their strongest effort to date — a Jimmy Eat World send-up in “Sex” — has been released as a single by almost every one of those projects before being completely rebooted as The 1975 in early 2012 with a successful string of EPs.

But despite that uncertainty and identity crises that seem to have developed quite an origin story, Matthew Healy and the rest of The 1975 have showed a penchant for relentless hooks and clever melodies. Those strengths were on display last night at the 9:30 Club, but that only managed to get them so far.

The highs were definitely up there — “The City,” “M.O.N.E.Y.,” any of the singles from the record, really — but the middle section of the set, dedicated to the mediocre numbers that bogged down the back half of the group’s album, nearly derailed the show. The mid-tempo crooners — like the John Hughes’ movie montage aping “Robbers” — felt flat and uninspired. The added saxophone cheese still didn’t do “Heart Out” any favors and was tacked on unnecessarily to other songs.

For a band that is as concerned with controlling its aesthetic, none of the shtick really shouldn’t come as a surprise. Scan any of the group’s outlets and you’ll see countless stark, black-and-white photos. So much so, it was kind of a disappointment to have to watch them perform in color.

The whole evening felt very controlled and calculated with everything appearing just so — hair, lighting, amount of wine in the bottle Healy nursed throughout the set. That effort to appear cool permeated the entire set, but the band seemed to drop the façade during the encore of crossover hit “Chocolate” and the aforementioned “Sex” showed why they’ve been one of the strongest alternative rock acts to come from across the Atlantic since the Arctic Monkeys. Here’s hoping they find out how to balance that style with actual substance.