i assume that it has to do with the android version, but there's no instructions, no nothing, how we should use those keys?
There were 200 codes sent to just people who already own the game on itch.io (at least that's what it appears to be). How many of those people own an Android device? I suppose it's possible for all codes to be used after 40 hours or so, but I'm guessing this was re-posted somewhere else, or the codes were gobbled up by a bot account.