Ngl I had the exact opposite expereince compared to IndieBen, I understood how to open the safe after clicking on all the things on it, but I had a lot of trouble dealing the the guy it felt like he kept waking up when I wasn't close enough to a closet before he saw me. The only way I got past him was by cheesing his AI, it seems if you agro him once and manage to hide from him, then he won't ever agro again.
Nice game, simple, clean, and fun. Although it would be nice to be able to skip the intro cutscene or be able to restart after you get caught rather than reloading the webpage