This is really, really good! I had a blast playing it. It looks awesome, it plays fluently, fighting feels 'impactful', as do the sounds. Sounds like an overstatement perhaps, but this is near-perfect, especially for a WIP game. Oh, yeah, also liked shooting holes in the potatoes. I would consider shooting off limbs or crippling them as well :-)
Found one bug: Reloading doesn't work with the shotgun, it only reloads when you switch to a different weapon and back again.
A suggestion: Implement using the scroll wheel (or Q and E for instance) to scroll through your weapons. Because of the limited ammo I found myself switching weapons quite often.
Oh one last thing: When you hit a potato (and don't kill it) it stops moving for quite long. Is this intended?
And indeed, if you build in more variation, more levels, perhaps some goals, assignments, it will be even better, because at some point it does get boring.
But, like I said, I really liked this!