Really, really loved it! So far, my favourite jam game for sure. I had a good time with it and got a little obsessed with 100%-ing it haha. If this is a demo, I am very excited to see you develop it further!
More mutagen upgrades and special sheep would be excellent additions. Some kind of active, limited-use abilities could also be a good thing to add. Currently you can kind of get screwed over if your sheep all lock on to one person or get stuck in an odd spot, or some human wanders to the very corner of the map, so active abilities to exert some control over sheep or just tag a problematic human with a dart gun or whatever would help alleviate that a lot.
Puzzles would be good too, and a better way of adding difficulty or interest to later maps than just adding tons of enemies. Having more controllable entities via active abilities would also provide you with a lot more design space to do that sort of thing as well.
I'd like to be able to play levels I 100%'d, but I see lots of people have given that feedback already.
I really, really enjoy the presentation here, even limited in scope as it is. The transformation animation is great, and I never got tired of watching it, although as a stretch goal, having 2 or 3 that play randomly would go a long way I think. The text that shows above people's heads in response to transforming or seeing others transformed was by far my favourite part of the presentation, I really got a kick out of it. The little details in the animation, like their eyes flickering between white and green as they give in to the TF, were also excellent.
Long comment, I know, but just had to say how much I LOVED this. I wish you the best of luck expanding it, because I would be thrilled to see more of it with a broader scope! :)