I liked the way that the player's field of view is obscured - This and the art style that you went with reminds me of Teleglitch, and Monaco.
Some of the instructions were not fully visible, so I ended up wasting my reload early on whilst figuring out the controls. I would then realise there isn't infinite reloads. A possible improvement would be to replenish spent ammo from a pool instead of using the full box. Shooting and reloading felt satisfying - the little gun twirl on reloading is a nice touch.
The inclusion of the theme felt a little tacked on, as there wasn't much in-game to suggest that it's taking place on a farm. If it were zombie animals, it might have fitted the theme better.
A retro-style zombie shooter on a farm.