I have killed one! :D
With my crappy headset I wasn't sure if sound was directional or not. I tried playing with my eyes closed, but didn't know which direction I was going.
Since you have clearily decided on going with "no visuals" wildcard and it's just a game jam I would experiment with it more. You could save a lot of time if you didn't implement so much UI elements and visual effects, only printing output to console for development purposes perhaps . I'm don't really have any suggestions what could be done here, as this seems like very difficult game to make and I didn't even consider it :)
As for the UI, there's too many bright colors. Gray always looks great. You can do a lot with just 2 or 3 gray colors and I think it would fit great to this game.