I think you should be proud over the fact that they cracked it and is spreading it around. I dont see anything negative coming from that at all.
Think of the promotion you are getting… Its free promotion and when the next game comes around they might say ***“hey, remember that game we downloaded before and thought was good but still downloaded and cracked?, lets buy the new game from this developer” ***
Its common to think that piracy is a negative thing, i would disagree on that point so hard.
I say congrats man, they are trying your game for free, and you wait and see, this will be good for you in the long run. If you were to say “Go ahead pirate it you want, but toss a donation to me, any amount will do”. You know what that says about you ? That you’re a good guy and not only in it for the money but also to spread your art.