Reminds me of a barebones roguelite game like Deadzone Rogue or Gunfire Reborn. As far as switching characters, a quick sound or maybe an on screen message reminding the player. I don't think I saw the character in the HUD until my third playthrough. Something to know that a room encounter is starting would be helpful too, like a 321 countdown because it was hard to know when exactly it was going to trigger after going through a doorway