The demo assumes that zkSNARK, circom, snarkjs and my usage of them all works as expected. At some point in the future I can reveal the Proof to demonstrate that I indeed know the hash associated with the Impossible location (the hashes are known: see the source code).

You could also remix the demo and choose your own hashes for each emoji (see console when searching for coordinates to get its hash), and I could then be the one guessing your secret coordinates.

The demo runs locally by the way (no server needed).