This summer has been notoriously strong for R-rated comedies. “Bridesmaids” has become the highest grossing Judd Apatow movie ever, and “Bad Teacher” is doing an unexpected amount of business as well. “Horrible Bosses" is the next major comedy to hit theaters this summer, and it suffers from some of the same problems as “Bad Teacher” — namely, a script that could have used a few rewrites. Also like “Bad Teacher,” it’s saved by a game ensemble; all of them hilarious.

The film’s titular bosses are played by Kevin Spacey as a manipulative executive drunk with power, Colin Farrell as a coked-out force of destruction and Jennifer Aniston as a fearfully aggressive dentist. After their bosses become too much to endure, their respective employees — played by Jason Bateman, Jason Sudeikis and Charlie Day — decide to kill them, hiring a “murder consultant” played by an energetic Jamie Foxx.

Films such as this live and die based on their cast, and “Horrible Bosses” has assembled an impressive ensemble. The bosses are used a bit too sparsely, with Aniston’s character disappearing from the film for much of its latter half. However, when they’re onscreen, they’re often hysterical, especially Farrell’s relentlessly sleazy manager.

The main cast is similarly uneven. While Sudeikis and Bateman both deliver a minor master class in how to make innocuous dialogue funny and funny dialogue hilarious, Charlie Day’s falsetto starts off as entertaining and quickly becomes more and more irritating as the film goes on. By the end, one wonders why anyone would be friends with Day’s character, much less place their legal fates in his hands.

Beyond an overwhelming desire to kill their bosses, Bateman’s and Sudeikis’ characters lack definition or personality. While Day is saddled with a fiance, she barely factors into the film or his character. The bosses are similarly underdeveloped, but Spacey and his cohorts milk their one-note characters, hitting the same joke over and over and somehow keeping it funny.

“Horrible Bosses” is a film with a bold, enticingly dark premise, but it also forgot to build intriguing characters around that premise. While it’s often hilarious, it’s a film that feels rushed and whose characters are barely more than plot devices. Nonetheless, the sheer comedic mass of its cast elevates “Horrible Bosses” into just north of mediocre, but still funny enough to recommend.