do we even know what the address that contains the 2.1 bitcoin reward is? i saw other people post a bunch of addresses, some even had balances but nothing that lead to this puzzle.
even if you wanted to brute force it, you have to know the address otherwise you're left with building a big blockchain index and then looking up the results that is not worth it.
Yes the address is well indicated on their contest post. If you check the address there is a balance of 1.1btc and the 1btc will be given to you if you proven that you already control the btc wallet. But the payment is on their website.
That's one thing about their puzzle, of course it will be hard to decipher cause the prize isn't small as you think. The winner of this puzzle contest will be indeed deserving knowing the clue is quite limited.