Rocket League is a team sports game. It has cars in it and it looks somewhat like soccer but really, it's its own thing. You play as one player on a team and everyone player on the fields is completely antonymous, which makes it feel like it has more in common w/ a MOBA or team based shooter than it does something like a FIFA game where you control whatever player has the ball. This individual experience draws you into each game and makes for a tense, fun online experience like no other in gaming right now.
What's really impressive about Rocket League is how it is accessible pretty much on your first game playing and later develops into a rather deeper game w/ much more strategy and skill without losing the initial fast paced fun that made it great to begin w/. You start off randomly making insane goals accidentally due to mistakes made by the inexperienced players you are paired w/ and move on having to make insane goals because it's the only way to get the ball passed the experts you are paired w/ later on. It is great and satisfying when you begin to be able to make pinpoint shots on the fly that you would have completely wiffed on few dozen hours before and simultaneously humbling when someone is able to capitalize on some small mistake you've made and punish you in the last seconds of a game. The learning curve is excellent and because of developer Psyonix's great-match making, Rocket League never even begins to bore you.
The gameplay modes are pretty barebones here which is actually part of the charm. You have one on one to four on four player matches and that's about it. You can play single player seasons but that's more for practice than anything. Ranked matches provide a challenge for experienced players and Psyonix throws in an occasional oddball mode for a bit of variation. Really, the standard three on three mode is more than enough given there are always equally skilled players online to play against; everything else is just gravy.
In short, even if you don't like sports games and even if you don't like competitive online games--and I really don't for the most part--this game is an absolute must play. It takes five or ten minutes of your time and turns it into a quick competitive blast of unmitigated fun. It takes a simple, easy concept and you can spend as much or as little time playing as you want and still have a great time. There are online games w/ more split second timing or deeper strategy but Rocket League stands on its own in terms of its accessibility paired w/ extreme replay-ability.