Not a big fan of MC calling Susan by her name now... that really ruins the kink.
Actually that goes for Cindy too...
The M/S and A/N dynamic is quintessential for this kink and without it it's just two people that haven't seen each other in a long time fucking. The B/S dynamic is different though it doesn't hurt to have a few e. g. "big brother" or "little sister" in it.
Apart from that not bad a game... even though I know where you got your inspiration from.