Wow what a deep review of my game, thank you for that!
I agree with your comment on difficulty, as i playtested, i got used to the game and controls and therefore had an easier time. I think i could have also done a better job explaining the way the game works too to aid with that (the higher you are, the longer the bullets take to hit you, you need to be so low etc.) I think the way id do this is to reduce the number of farmers that spawn at the beginning exponentially. id also in turn like to make the rpg farmer have more impact on the experience. The poo attack could also use a crosshair or something similar i believe.
thank you for playing my game and taking the time to give such an in depth review.
Keep being a boss!