It's more likely than you think!

Our 2nd programmer wanted to try to put online leaderboards in our game. I didn't imagine it would be possible, but he really wanted to try it and he came back the 2nd day with it working. I think it added a lot of replayability to our game and a handful of users went in hardcore and achieved some level times I could hardly imagine were possible.

We've posted the source code for our high score server on GitHub along with an example of how to communicate with it from Unity. It can be hosted on Heroku which is what we're doing. It's unbelievably convenient and free with light usage.

Server Code Github: https://github.com/midblue/highscore

Consider checking out our game, in addition to the leaderboards, I think the rest of the game (The parts I was involved in) also turned out really well :P

LDJam Link: https://ldjam.com/events/ludum-dare/46/final-flower-petals-of-a-lost-age