In the face of AAA games with multi-million dollar budgets, Rocket League a considerably smaller offering to me is more fun than most of the purchases I have regettably made this year like Battlefield Hardline or Dragonball Xenoverse.
I bought Batman Arkham Knight about a week before Rocket League came out and I now find myself preferring to play Rocket League than Arkham Knight, Destiny, GTA V or pretty much any other $80 I have purchased this year. This is a pretty huge testament to the developers and the game itself.
Harking back to the golden days of 90's gaming where learning the controls was easy, but mastering the game was more difficult, Rocket League combines that nostalgic 90's gameplay and steps it up with a nice physics engine and balanced gameplay.
This is one of those games where I like it so much, I will gladly support the developers by buying DLC for it. Take note bigger developers and publishers, this is how you make a fun game. Not everyone just buys games for fancy graphics or storyline, gameplay is first and foremost one of the most important aspects of any game (old or new).