As I was trying to wake up and get moving today, I fell asleep for about fifteen minutes max. (I looked at my clock before and after the nap, and the two times were fifteen minutes apart.) During that time, I had a fairly-complicated dream that seemed to take much more than fifteen minutes to experience.
How rapidly do dreams occur?
My dreams are complex, and can involve all the senses (although this one didn’t have a lot of smell). Is my brain doing the same amount of work while experiencing a dream, as it would while experiencing the same amount of wakefulness? In this context, I’m not sure whether “amount” would mean “amount of apparent time duration” or “amount of complexity of experience” or what.
Sometimes I have a vast and complex dream that ends with some sound from the waking world woven neatly into the plot. But the sound is coming from outside my head–does that mean the whole dream took place in an instant when the sound started? Or is the plot of the dream adjusted to fit the sound as it occurs?
A memory of a long dream in a short sleep doesn’t necessarily have to mean that you experienced it in rapid-motion; it could be that some or all of it is a false memory; something that you only remember having experienced, when in fact the memory was plonked in there fully-formed (like Total Recall, only more plausible and without the triple-breasted mutant whores, well, mostly).
For me, dreaming is a form of perspective time travel.
I also experience long dreams in the short span between snooze on the alarm clock. 
FWIW, I’ve had complicated, involved dreams in between pushes of the snooze button on my alarm clock (8 minutes.)
Are you sure that you dream was as complicated as you seem to remember?
For instance, I had a complicated dream this night, including a plane crashing on a building. Since the dream was quite impressive, I thought about it when I woke up. However, though the whole thing would have taken quite a long time in real life, I’m not convinced it did in my dream. For instance, in dreams, we often “jump” from situation A to situation B. When remembering the dream, if we don’t pay attention to the details of it (which is pretty difficult), we can “remember” that we, say, walked from our office to the river bank, which would took some time in real life, while actually in the dream we we’re in our office, and the next instant standing by the river bank.
That’s what happened in my tonight’s dream. There was several such “jumps” from a situation/place to another situation/place and aparently no time elapsed in between. It seemed to have been a long dream when I woke up, but actually, when I tried to remember it more precisely, though convoluted, the whole string of events didn’t take that much time, due to these “jumps”.
The plot can certainly be “adjusted”, at least in my case. From time to time, my radio-alarm clock sounds are included in my dreams (I often have a hard time waking up). For instance, recently, I had a dream which was happening in a train station. During my dream, the train station loudspeakers, instead of giving the departure times or such things, were giving the news. Of course, actually, it was the news broadcasted on the radio.