After discovering 2 of 4 tiles from a column left to 3 basic elements, i was sure that the rest 2 also would require merging of two tiles. That's actually the 2nd (not prime) reason why TWO fires are needed to be merged with a tile (which in reality could be easily burnt starting from just one match) is ultra-counterintuitive! So i could discover 3rd element from the leftest column only out of pure accident. Also, it makes thinking of 4th tile from that column much harder, because amount of possible combinations grows exponentially! Maybe it's quite easy and obvious for you, makers, but that tile and "scorched earth" are only two things that left unclear for me in your lovely game