I love your game! I actually liked that the shadows were a little harder to spot and you had to use sound a lot of the time to guide you towards animals. Half-way through my run i started recognizing the sounds that the animals i needed made and started hunting them down - As a sound person, I love the use of sound here and would like to see that expanded in the future.
The only complaint that i have is that my animals (specially raccoons, those freakin' raccoons) started stacking on top of each other and escaping their pens. I thought i was hallucinating for a few minutes but then i just pointed my flashlight at them for a bit and saw them committing their great escape.
The upgrade system is great, specially the flashlight upgrade that helps with catching animals.