The opening factory shots remind us of the "software construction" metaphor. But the fact that this section fades out quickly is a nice bit of foreshadowing: big design up front is dying out, with something new to come. Considering the movie's age, this introduction of agile methods is near-astounding.
From there, the film quickly switches to the Joliet Correctional Center: certainly a sign that we are dealing with the typical project where the developers feel trapped. And indeed, we quickly meet the lead developer: Jake Blues, who is being released from prison (that is, completing a project and moving on to his next opportunity).
Jake meets up with his partner Elwood in a typical small consultancy. We get a hint early on that Jake and Elwood are not ordinary developers, but super developers, literally able to leap a drawbridge (with the aid of an ex-Mount Prospect police car) in a single bound.
We shortly meet the new client: St. Helen of the Blessed Shroud Orphanage. Like many clients, they have a deceptively simple problem that they want solved. And like many clients, they have no real idea of what solving this problem will entail. The boys try to explain the difficulties in getting $5000, and end up getting beaten with a yardstick and thrown down the stairs. Anyone who has ever had to deal with a difficult client will sympathize.
Jake, as lead developer, is tasked with coming up with the project plan. He is at a complete loss until suddenly a light from the heavens hits him, and in one burst of insight, he sees how it will all come together. This is the architectural phase of the project, and at this point, the promise of the software is limitless.
Of course, as in all projects, the plan does not survive contact with reality. Jake and Elwood get pulled over by the cops for speeding, and given Elwood's record, it seems like the project is doomed from the start. Jake resigns himself to early failure. But insisting "They're not gonna catch us, we're on a mission from God," Elwood leads the cops on a chase through a shopping mall, ultimately escaping. We see here the role that a good pair can have on a programming job: when one half of the pair is temporarily stuck, the other can step in to finish the current code spike.
The next step, of course, is to assemble the development team. Jake and Elwood find their team in unlikely places: a church, a row house, a Holiday Inn, a fancy restaurant, a soul food cafe, a pawn shop. Experienced project managers will understand there is no substitute for talent, wherever it can be found - and that often talent is not associated with college degrees or cleancut young people. Putting solid effort into the hiring phase of the project has substantial benefits down the line, when the whole team comes together seamlessly - just like the Blues Brothers' band.
Every software project seems to have one insurmountable obstacle, and this one is no exception. In the case of the Blues Brothers, the tough bit of coding is represented by Jake's wife, who shows up with heavy ordnance at this point in the movie (and repeatedly thereafter). The developers have multiple tries at implementing the desired feature, but they seem unable to succeed. What developer has not had the experience of a completely intractable bug that defies multiple attempts at a fix?
After assembling the team, it's time for the first coding iteration. In the movie, this is represented by the first gig at a country and western bar - and it's a near-disaster. The team does complete the iteration, but the client is dissatisfied and they slink away to regroup.
Development must go on, though, and the team meets in standup fashion to figure out what to do next. Amusingly enough, the metaphor for the standup meeting has them all sitting down - but in a steambath, which certainly matches the tone of many daily scrums. They come out of the meeting with a new plan, which is followed by lots of hard, routine work - in the film, these successive iterations are telescoped into a montage of scenes promoting the gig at the Palace Hotel Ballroom.
The climactic concert features the development team overcoming a variety of obstacles (angry Nazis, a rival C&W band, the members of the Illinois law enforcement community) to turn out a superior product: a successful final iteration by any measure. The client is happy with the results, as symbolized by the $10,000 advance on a recording contract.
But of course, after the software is finished, it has to be delivered. And, like so many developers before them, the Blues Brothers underestimated the difficulties of deployment. Elwood realizes this in one of the movie's signature lines:
"It's 106 miles to Chicago, we've got a full tank of gas, half a pack of cigarettes, it's dark, and we're wearing sunglasses."
Jake's response? "Hit it." As lead developer, he knows there is no way to get past this problem except to work through it. Deployment is a long slog, with many obstacles. There are dozens of (literal) crashes involved. But, absolutely right at the deadline, the brothers make the property tax payment symbolizing a successful product launch.
And their reward? As shown in the last ten minutes of the film, their next job is back at a prison - very much like the one that Jake thought he had escaped at the beginning. That's the final lesson of The Blues Brothers for software: a developer's job is never done.