I paid one cent for the game (actually, I paid two cents for it, as the site crashed on me during the first transaction and I was forced to do it all over again). I don't feel bad about it, though. Fact is, for me this game wasn't worth buying. I tried the demo and it was pretty enjoyable, but not enjoyable enough that I felt like spending money on it. However, if offered the chance to get the game for free, or in this case almost free, then sure, I'll take it. How exactly am I a pirate? 2D Boy told me to pay what I felt like paying and that's what I did.
Your argument is just as bad as claiming that a pirated copy of a game, song, movie etc. automatically equals a lost sale.