To begin, we close our eyes. We are told to imagine a science fiction-esque film about a phone booth that is really a time machine from a distant future. Now imagine that time machine is used to hop through time on a whim, interfering with history in some way, and making sure the future remains the future and the past the past, all through the use of this time machine. Now imagine all these important historical figureheads show up and jaunt through time with the main character and his companion. Except the phone booth isn't bigger on the inside; in fact, it's kind of small-ish. Wait, we're talking about Doctor Who, right? No, we're talking about what Doctor Who might be if Pauly Shore and Adam Sandler wrote it-- the 1989 classic Bill and Ted's Excellent Adventure, one of the first breakout film roles for Keanu Reeves (and who doesn't love a young Neo?).
Although the premise is similar to Back to the Future (except without the creepy Oedipus story going on) in which a couple of guys start messing with the timeline to insure the future remains intact, Bill and Ted takes it to a whole new level: pure comedy. The entire movie is a depiction of what would happen if two "rockstar" teenagers somehow become the key to the future as we will know it (according to George Carlin. It is a comedy, after all). Just looking at the poster to begin, one is allowed a glimpse into the "reality" that the film presents, including both references to history and the importance of time throughout the film. The taglines for the film read "History is about to be rewritten by two guys who can't spell," a jab at the characters' intelligence as well as foreshadowing their importance, as well as "Time flies when you're having fun." The main characters are sitting atop a phone booth (completely relevant to the film, but not having the relevance given away by the poster) in which historical figures are seen crammed shoulder to shoulder. This isn't to ignore the fact that the entire setting of the poster shows the group floating in outer space.
The entire film and the use of time travel in the narrative itself rests on the basis of causality and piggybacking from paradox to paradox, opening and closing time loops and oftentimes leaving questions "unanswered" simply due to having them answered earlier in the film (due to the nature of the time travel). The story begins with a monologue by Rufus (George Carlin) that poses and answers many questions without the viewer even realizing:
"Hi. Welcome to the future, San Dimas, California, 2688, and I'm telling you it's great here. The air is clean. The water's clean. Even the dirt... is clean. Bowling scores are way up. Mini-golf scores are way down. And we have more excellent water slides than any other planet we communicate with. I'm telling you this place is great. But it almost wasn't. 700 years ago, the two Great Ones ran into a few problems. So now I have to travel back in time to help them out. If I should fail to keep these two on the correct path, the basis of our society will be in danger. Don't worry, it will all make sense. I'm a professional."
Now right away, the viewer is both confused and informed (if they are a first time viewer). The character Rufus lets the viewer know the timeline (2688, 700 years in the future compared to 1988) as well as the fact time travel is a thing, why Rufus is using time travel, and that other planets presumably have life (as he describes it, but not what kind of life). But he brings up a few questions to be intentionally confusing. He notes, "So now I have to travel back in time to help them out," meaning he hasn't done it yet. But he notes that "...this place is great. But it almost wasn't," as in history has already been fixed. But how has it been fixed if he hasn't gone back in time to fix it (assuming he was the one that originally set history straight)? He continues, "If I should fail... the basis of our society will be in danger," thereby confirming that the "saving" hasn't been done yet but also that there's a possibility he might fail, thus causing a different future that is, in fact, in danger, but he would only know that if informed of the danger from the future, but then if he fixed it, how would that future happen. And why is George Carlin not swearing in this movie? But alas, he confirms it will all make sense.
Throughout the entire film, the use of time travel causes for slapstick type moments of comedy or moments the viewer will say "Ohhhh, okay. I get it now," without even realizing that they were supposed to have noticed something important earlier in the film. There are a few primary examples that will unfortunately be spoilers for anyone who hasn't seen the movie (sorry, but it's nearly 30 years old, deal with it), but I will only note the first and arguably the most important. Early on in the film, Ted's dad has lost his keys and suspects that Ted has done something with them and/or lost them. When asked about having done something with them, Ted replies, "No sir." But this is foreshadowing of "Chekhov's gun" proportions (Thanks, TV Tropes!) that will come up at least twice nearly at the end of the film (in chronological scenes). When Bill and Ted have to break the historical figures out of jail for causing a ruckus in the local mall, they realize they need Ted's dad's keys to do so (as he is on the police force), but realize they "don't have time" to steal them. They then come up with the idea to steal them after the presentation and leave them for themselves before the presentation--behind a sign they are conveniently standing next to. After creating a ruse to lure Ted's dad away from the cells, the pair begin to break the historical figures out of jail, only to be caught by Ted's dad. Using the same comedic method of time travel, Ted closes his eyes and tells himself, "Trash can. Remember.. a trash can," only to have a trashcan adorned with "Wyld Stallyns Rule!" land on his head out of nowhere. As the scene ends, Ted states, "Oh, by the way, I found your keys!" and lays them visibly on the jail cell bars, thus closing the paradox they created by stealing the keys (from before Ted is asked about them at the beginning).
The film conveniently and creatively pokes fun itself in many ways, especially when referring to its own paradoxical nature, as well as provides the viewer a foundation for which the understanding of the film will rely. At the beginning of the film, Bill and Ted are arguing about creating their music video for their band Wyld Stallyns, after causing their poorly functioning equipment to start smoking during their shoot:
Bill: "Ted, while I agree that in time our band will be most triumphant, the truth is Wyld Stallyns will never be a super band until we have Eddie Van Halen on guitar."
Ted: "Yes, Bill, but I do not believe we will get Eddie Van Halen until we have a triumphant video.
Bill: "Ted, it's pointless to have a triumphant video before we even have decent instruments.
Ted: "Well how can we have decent instruments if we don't really even know how to play
Bill: "That is why we need Eddie Van Halen."
Ted: "And that is why we need a triumphant video!"
The entire discussion wraps itself in its own argument, using one point to answer the other, leading to a paradoxical form of causality, which is the entire premise of the film as well as all the events that occur. The future can't exist as it is without Bill and Ted passing their history report and staying together to form Wyld Stallyns (the greatest rockband in history). Bill and Ted can't pass history without going back in time to get historical figures for their report, but they can't accomplish that without the help of the other historical figures they're gathering. The historical figures can't be rescued without Bill and Ted going back in time to get keys to rescue them, and none of the figures can be brought to the future without bringing them back to the past first. And lastly none of this can happen in the first place unless Bill and Ted almost fail their History class (and causing the future to be in peril, which creates a crazy time paradox wrapped in more paradox). But all of this can only happen in the matter of a single day, the time allotted to the pair, because as Rufus notes early in the film, "Gentlemen, you can do anything you want, as long as you remember this: no matter what happens, you must get to that report... Now, most important, no matter what you do, no matter where you go, that clock, the clock in San Dimas, is always running."
Overall, Bill and Ted's Excellent Adventure provides a classic and, most importantly, humorous take on what time travel can be used for in film. By using concepts of causality, paradox, and time loops, Bill and Ted (the characters) are able to overcome a great many obstacles (both in time and place) in an effort to pass their history report. Many of the elements and use of time travel are explained throughout the film, leaving few questions unanswered. Paradoxes and time loops are created and closed and the reason for their use becomes a part of the narrative itself, often done humorously. The entire movie is otherwise nonsensical and meant only for the sake of humor. Rather than being an entirely social critique, the film instead uses many pop culture references and in-jokes for comedic purpose. However one critique most excellent is presented by the narrative. Rather than using the time machine for nefarious purposes (as it seems they're trying to do), they use it for actual educational value, not only traveling back in time to gather the historical figures they are going to use for their report but also experiencing the world and culture of those they're using. The film shows that even though the duo attempted to take the "easy way out" to pass their class, they ended up in a much more difficult (albeit hilarious) situation that resulted in them learning the same material they should have been learning all along. This commentary shows that many paths may lead to the same outcome (studying and doing the work vs. using a time travelling phone booth to take people out of history and nearly dying multiple times), but the effort toward that same reward or outcome is often disproportional (with some paths being much higher risk for the same reward).