I'm just making something up as an example here. If on one screen you had to step three times to the left, go forward once, pinch the ass of a goblin to the right, then hop forward twice on the 3DO version every time, you may not have to do those exact steps in that order on the arcade version every time. The steps you must take supposedly aren't always the same.
They might not all be exactly the same but they were pretty close. I was like esposta and could get to the end in one man and on the last move (where you throw the sword) I wouldn't hit the button, so I could play that entire sequence again, and get the maximum points. I have the 36O version and never noticed a wildly different pattern when playing. What I did notice is it seemed to be on a HARD setting which couldn't be changed in the home version and ment that you had to have your timing just right or if would count as a death. The Dragons Lair at my local arcade must have been on a forgiving setting. (Easy) They gave you 5 men to start, and with a few exceptions as long as you knew the next move, (example: Left) you could just hit the joystick left over and over, it's would make a dull noise until the move was valid in the game then it would make a high plink noise that ment it registered, and you could then start doing the same for the rest of the moves in the sequence. As far as lots of different choices, there wasn't really a lot. One that came to mind was the rapids sequence you could either push forward if you were directly in front of the opening, or left or right earlier depending on where you were in the water. The difference probably was you could only use the forward at a very particular moment and would have gotten more points. These type of "not chiseled in stone" moments were not common though.From what I recall, for the majority of the game you have to take the same steps every time or it's a death.
Not sure how Dragons Lair would translate to an Atari 2600, but I'm sure it could be done! It worked for Halo.