This mastery system is quite broken

Did you seriously take the photo with your phone and not just screenshot commands? WTF... Kids these days. Mastery of Computer: D-.

You were playing riven.

You're only missing about 200 cs :)

riven what broken. U are expected to not die at all to get S+ with him.

Averaging 6 CS a minute, 5.8:1 KDA, the only thing is the 8 deaths, but you were front lining so, can't be helped.

The fact that this game had no supports in it kinda blows my mind, even in Bronze. Amumu tried to make up for how absolute terrible Ekko was. Maybe that's why it's an S- you beat up kids that couldn't defend themselves.

Ok so the rankings are based around your mmr (from what I have read) S- means that your score is the average for riven players at your mmr. From what I have seen (playing bard) an S+ was 8/4/37 with somewhere around 100 cs in a 37 minute game.

As riven in a 57 minute game you should have gotten about what you got seeing as you only had 27 kills and 327 cs

died 8 times.

Didn't upgrade trinket. Failure

15 wards in 52 min despite carrying a warding totem all game. I guarantee you that's why.