If you don't know what Rocket League is, you must have been living under a rock in the past month or so. The sequel to Supersonic Acrobatic Rocket-Powered Battle-Cars quickly became the summer hit, with more than 5 million downloads.

　　AMAZING! More than 5 MILLION downloads since we launched on July 7! Your continued support for our game is truly humbling. Thank you.

　　— Rocket League (@RocketLeague) July 29, 2015

　　Of course, being featured among the free PS+ games of July helped a lot, but Rocket League is also extremely popular on Steam (it's currently at the very top of the selling chart). Perhaps you didn't know that the game could have been entirely free, though, as explained by Psyonix president Dave Hagewood in an interview with PC Gamer.

　　We briefly considered whether we should go the free-to-play route. We’ve had a lot of experience with free-to-play. We’ve had ups and downs with it, and we don’t see free-to-play as being a definite, automatic “you’re gonna get a million people playing your game,” as some people do. I think there may have been a time at which a free game was kind of a novelty, like “oh my gosh, this game is coming out for free,” but it’s not anymore. You’re competing with a lot of other free-to-play games. We saw a lot of people have been turned off by that model, and we’ve really built a theme around this game about trying to listen to our fans and see what they really want. Not necessarily what’s going to make us the most money or what’s the hottest thing going, but what do people really want? What is gonna make us popular in the eyes of gamers and make them talk about us and say “this is a company that really gets it.” That’s what we want. That’s the kind of message that we wanted to hear people saying, is that at least one company is willing to listen to what the fans want and deliver on that.

　　So we decided we wanted to go more, you might even call it the ‘old school’ or traditional way of doing things. You pay a price for the game, we have DLC but we’re not piece-mealing it out—you know, you pay $1 dollar for one hat. We’re giving you a big pack of really cool stuff, we don’t want to overprice it. And we also want to give out a lot of free DLC as well, just to keep people playing. Because we believe as long as we keep supporting the game, we keep having people come in and buying the game and telling their friends to buy the game, we don’t really need this microtranscation based model.

　　It's worth to remember that Psyonix is already handling a Free-to-Play game, Nosgoth. Clearly they had enough elements to make their decision, and given the growing disdain of the public with the F2P model they may have made the right one.

　　Hagewood also teased modding support for Rocket League, which the studio is considering right now.

　　We’re talking about it. One of the challenges is because we’re cross-play, and the cross-play means everything has to be updated on both the PC and the PlayStation version. So that’s a big challenge. I can’t go into it, but we’re already working out some really interesting ideas on how we can start working with modders and user-generated content.

　　Rocket League is out now on PC and PlayStation 4, but a recent GameZone interview hints that more platforms (likely Xbox One) are coming. Check out our review of the game, if you haven't already.