Thank you for playing! I do plan on revisiting and improving post jam, so I really appreciate you bringing those bugs to my attention.
We initially planned on having a goblin war cry as an indicator of each wave beginning but the sound effects we had didn't really fit the environment or the theme. Something I do want to add is player and goblin footsteps alongside some more (scarier) sounds for the goblins - maybe there should be some really subtle audio queue for round begin indication, but you make an interesting point about the lack of information keeping players on edge.
If you have any other ideas or suggestions I'm all ears!