We noticed an issue with the provably fair implementation which allowed anyone with access to the non-encrypted server seed (i.e. me) to predict the outcome, obviously I wouldn't cheat. However, this has now been fixed by recording the current block number when each guess is placed and posting it along with the guess details.

We take the block number of the final guess in a game as part of the seed for the random number generator.

This post has been updated to reflect the change.