This game is cool.
But wow, art is special... maybe you shouldn't resize your sprites, it pixelates them and it's not pleasant to watch.
The thing which upset me totally is your texts. I cant' see my score ! Your background is brown, and the text is brown, so how can we see it ? I gave score as example, but it's the same for every texts.
"Game is extremely difficult". I don't think so. I scored 6442, i don't know if it's a good score but i think i have reached the 5,000 you told.
I had to try a lot, because sometimes rocks of both side are joined. I don't have any way to go through. Nevertheless, it's addicting.