The low level view is best used when in combat as it's the only way to easily keep track of health bars outside of the squad menu. (invisioncommunity.co.uk)
Since monsters don't have health bars in this game you have to go off of more direct body language and visual cues. (gamecrate.com)
Any enemy that has a large health bar on the bottom of the screen when engaged in combat is considered a boss. (speedsouls.com)