Thanks for the feedback! Yeah, you're absolutely right about the lack of explanation and somewhat poor UI. I was aware of this while making the game but couldn't find the time to make a proper menu or tutorial due to starting two days late.
Oh, also if I make a post-jam version I'd probably add a per-player arrow setting, or just make a ton of directional sprites so it's more precise. You can look at the sword to pinpoint your exact direction if you already know roughly what direction you're looking in, but it could be more clear, I agree.