I think their are three reasons for it:
1.
Most of the scene has the same elements: Girl alone, Blowjob, sex and anal, dp, facial... and then it all starts over.
Would have loved it when some rounds don't have the whole package for example a blowjob only round which doesn't has sex in it or a round focusing on blond girls or on a specifiv pornstar, something that makes the round "special".
2.
The scenes are all from similar websites like ElegantAngel and 21sextury.
So these sites are great but when you know one scene you know them all
3.
Every scene felt like an "endurance" round and there wasn't much variety in the beats, I like it simple but when I stroke for such a long time I need some variety.
So not that you get me wrong the scenes are great and I love the hardcorestuff but I think they do not work well together for such a long time. I will definetly keep this movie and put it into the randomiser
Cheers




