One element that sets 173 apart from other games of the same genre is that it has a blink button - and you have to press it. Unfortunately, blinking makes it easier for 'the creature', whatever it is, to hunt and kill you.
You would be wise to keep yourself surrounded by light at all time. You can start by using an ember from the bonfire, but as you advance, you'll need to find other sources of light.
Exploring in the dark is not at all easy. Not only is it difficult to move around - blinking constantly - you also have to take into account the tension produced by knowing that you could die at any moment.
173 is a truly terrifying first-person adventure that will keep you holding your breath. The best part is, although it has some things in common, it's not just another remake of Slender.