Thanks so much for trying it out!
Yes, the UI can be a little finnicky when not in full screen.
I did try killing the spiders at dawn. The problem with that was that many spiders didn't even reach the cabin by dawn. This suggests the spawn points need to be closer to the cabin, but I didn't have time to tinker with that.
Unfortunately there is not always time to balance the difficulty in the context of a jam! I may return to this after the ratings period.