I will quote what bigreddit machine posted here:

>The challenge in a sense has a "trusted setup," meaning that creator (in this case /u/Riiume) could at any point submit the correct answer. The rules require only that the final destination address be submitted, which the creator (whoever that may be) would know. When the challenge is funded by the creator, the only motive to cheat and submit the correct answer (under a pseudonym) would be as an attempt to FUD Monero's unlinkability. But, if the funds are coming from anyone other than the person doing the setup, that person could submit the correct answer and win the money. Of course there the Catch-22 associated with the fact that a correct answer would likely lead to a drop in the price of XMR, but free money is free.

So, we have all the good reasons to suspect that the 1st challenge was a just a farce to make the community buy into the fundraising. The author of the 1st challenge was at 0 risk of losing his funds, since you can't really determine the address from an output. For more info, look here.

I believe the author is fully aware of this, otherwise he wouldn't offer his funds for the 1st "game", and it was just the first step of a sophisticated scam.

Judge for yourself. The only way for someone to determine the address is if the game creator leaks some info or is hacked.