Despite increasing problems with sickness due to his fight against colon cancer and an ever-continuing demand for his services, Goldsmith managed to produce just that: an exercise in gag reflexes and genre references that moves at the speed of light through stereotypical statements of theme and instrumentation. The score serves as a surprisingly thorough culmination of all the campy comedy elements that he had employed over the second half of his career. Unfortunately, time did eventually catch up with the composer. Goldsmith didn't have the strength to finish the score for Looney Tunes: Back in Action due to countless late edits to the end of the picture, and John Debney, likewise versatile in this particular genre and a master of imitating the style of other composers, was hired to use Goldsmith's ideas to formulate an additional 13 minutes of material for the movie's final reel. (Goldsmith was an admirer of Debney's work and thanked him for his assistance with a generous gift of an expensive watch.) Orchestrator Mark McKenzie, by then a frequent collaborator with Goldsmith, was tasked with adapting a number of classical pieces into the work as well. When the studio decided to replace certain pinpointed moments in Goldsmith's score with actual Carl Stalling music, they brought in Australian composer Cameron Patrick, who was a foremost expert at transcribing Stalling's genre work, and a few of Goldsmith's cue were replaced by these brief explosions of old favorites. Still, Goldsmith's work is the defining character of the soundtrack as a whole. His techniques here could only be suitable for a cartoon, and classic slapstick composers for orchestra in this genre, including Stalling and Raymond Scott, would be proud of his adaptation, accessing the same musical vocabulary but expressing it in purely a Goldsmithian voice. At the very least, it showed that Goldsmith's mental talents were still firing on all cylinders to the very end. The amount of orchestral energy unleashed through the rhythms, instrumentation, and tempo of Looney Tunes: Back in Action is staggering. It's a score that needs to be appreciated even if it can't be enjoyed because of its rapid pace of directional changes.

Being for a wacky cartoon, the score for Looney Tunes: Back in Action inherently needed a series of short cues, often with unrelated genres in each sudden succession, and the tone is therefore difficult to tolerate unless you know exactly what you're getting into. The references to other scores and genres alone, however, will keep a film music collector interested for a few listens. A theme for Daffy Duck debuts in the middle of "Dead Duck Walking" and is suspiciously similar to one of the plethora of pleasant ideas for The 'Burbs, and it is stated enough times to establish itself well in the score. A loungey electric guitar-led motif also exists throughout the work, representing the studio-inspired espionage aspect. At times, the guitar explodes into rhythms that mirror those heard in Edward Shearmur's parody style for Johnny English earlier in 2003. A slide guitar is a common contributor during these moments, too. Goldsmith utilizes a variation on a famous Western theme to represent "The Bad Guys" in the score. When the setting turns to "Area 52," Goldsmith reprises that eerie, distant vocal from The 'Burbs and brackets it in between violin slashes from Bernard Herrmann's Psycho. And whenever being "In Style" is mentioned, a lofty, classical solo violin of pretentious attitude is offered. For scenes of ritualistic action, such as in "Blue Monkey," Goldsmith revisits snare-led martial ideas from Small Soldiers. As the setting changes to Paris, Goldsmith pours on the stereotypical accordion, and when we meet the jungle setting, a variety of drums greets with primitive intentions that vaguely echo Congo. There are a few cues of unrestrained bombast for brass, timpani, and electronic rhythm-setters, such as "Dead Duck Walking" and "Free Fall," although most of the faster action pieces rely on Goldsmith's creative use of percussion to provide their attractive accompaniment for the quirky characters. As Stalling did in the classic cartoons, every conceivable piece of percussion was pulled out for this score, from the basic ramblings on the piano to whistles, rattles, triangles, and joke-accenting noisemakers. Goldsmith even incorporated a harp into the proceedings, which was a rare event for him. (His hatred of the instrument was a well-known source of amusement for decades.)

Goldsmith's sense of humor was unwavering, as usual, with a full reprise of his Gremlins theme when an appropriately named vehicle is whipped up in "Out of the Bag." The flighty tone is a characteristic of Looney Tunes: Back in Action that you have to be prepared for in order to enjoy the score on album. There's certainly a large contingent of film music collectors who have no affinity for Stalling's style or even Goldsmith's comedy material for Dante films, and for these folks, this score was a disquieting way for Goldsmith to exit the stage. None of Debney's last-minute material appeared on Varèse Sarabande's original 37-minute album, though his music did have a habit of readily spreading around the secondary market. The label finally offered a "Deluxe Edition" of the score in 2021 that finally provided Debney's four critical cues from the end of the picture. His music, while making use of a few of Goldsmith's themes and noise-makers, is distinctive in its more robust and consistent flow of action. Some listeners may find his contribution to be far more palatable on album. The 2021 2-CD set also includes the full range of McKenzie and Patrick contributions, as well as the raw recordings of the music that Goldsmith recorded for cues that were stricken in favor of the Stalling moments arranged by Patrick. Most of these cues contain studio chatter at either end of the take. The second CD also includes a remastered version of the original Goldsmith-only album presentation. The sound quality of the recording on both products is surprisingly flat and dry, containing none of the ambient vivacity heard in Small Soldiers. Overall, Goldsmith's slapstick material for this film is well developed but not as concise and enjoyable as his own standard of classic parody in The 'Burbs, nor does it have the same electronic creativity. That's likely due, once again, to the speed at which the scenes and moods in Looney Tunes: Back in Action change. It's a very specific sound for a very specific mood, and it should best be left for the marvel of its own construction rather than expectations of a coherent listening experience. With the rejection of Goldsmith's score for the underachieving Timeline earlier in the year, this was his only completed screen credit in 2003, and when he succumbed to his cancer the following summer, Looney Tunes: Back in Action became an arguably unceremonious conclusion to a great career.   @Amazon.com: CD or Download