Not that bad. I think I found a glitch where if you have no cows, the monsters seem to just... freeze and not attack. Also, the monsters per wave and how strong they were ramped up way, way too quickly in my mind.
Also, the dialogue was nice to read! Though I would personally make the dialogue pass with a different button or something, since I passed by some when I was feeding the cow.
I want to put it here, in case you see this. There's a thing if you edit your page that specifies the size of the window for the online version. Currently the online version is way too zoomed in, so no one can play it online right now.