SPOILERS?
for me the way I got it was on day one I went to the rooftop instead of going to lunch with the group, which later made Crowe text us to meet him out front, then leading to a choice to kiss him, choose that and you should get it :)
Viewing post in [ VERSION 2.3 NOW LIVE! ] + GUIDE comments
when you click the download now button you will get a message that says "This game is free but the developer accepts your support by letting you pay what you think is fair for the game." pay the 5.00 dollars and then you will be able to get the paid version. And after you buy it one time you don't have to buy it again. In you "My library" tab you have a tab that says "Things you own" and you download and you will be able to download again.