Probably referring to the book/novel rather than the movie, as the book is autobiographical in nature and a fascinating read, while the movie is more pure entertainment.

Edit: actually scratch that, I have no idea (obviously) what the author had in mind, and could be either.

The book had two of the most enduring images in all of modern literature.

The first, that occurs in a Cadillac convertible bombing toward Las Vegas at 90 mph, has the author seeing big black, bat-like things swooping around the car, and choosing not to mention them to his companion: "He'd see them soon enough, poor bastard."

The second is in the lounge of a hotel on the Strip, when the author suddenly realizes that everyone else in the room is a vicious, bloodthirsty reptile, and the whole floor is a puddle of shed blood.

I wouldn't call the movie pure entertainement, quite the opposite. It can be seen as that, but there are a few scenes that really stays with you if you've ever fooled around with drugs. The most obvious ones are when the narrator talks about San Francisco in the 60's, and when he talks about the "fallacy of acid culture" near the end. There's also something to be said about the "white rabbit" scene, though it's hard to put into words.

The scene in the casino waiting room/bar where things start to drift from normal to absolutely crazy (reptiles and all the blood) and then snaps back to reality is a pretty accurate depiction of LSD

Edit: I’ll add that “snaps back to reality” happens if you’re lucky and somehow stay in control

I don't think there's any "accurate depiction of LSD". This wasn't at all my experience with LSD, but this looks like it is for some people.