After watching the video, I kinda agree with Lane. But to be less blunt, the problem with all these "plays" is that:
A) you were clearly ahead in levels, probably in items too; coulda just killed anybody without using abilities
B) enemies were outnumbered
C) none of these took effort to do/nothing flashy was done especially when considering the above
Now, if you had like 100 HP as Zed and you killed three people at the same time even though they're a level or two behind, then it's legit. Faker vs Ryu Zed clip is a good example. Faker killed Ryu after retaliating only when he was clearly in a disadvantage and won the fight anyway.
Now being level 18 as Rengar and one shotting a full HP lvl 14 Ashe is no big deal. You even used flash for her someone who's already useless. She got more out of that than you did.
As a guideline, consider a play to be something that you shouldn't be able to do if your opponent(s) is equal to you in terms of skill level.