This is a neat little game. I found the first puzzle a bit too difficult (I'm not really one for codes) but for the most part the puzzles integrated well. Aesthetics and sound design were good, but the horror factor was missing for me. I liked the music a lot and it built some tension, but ultimately wondering around in the dark going back and forth between rooms lost its creep factor after a bit. Adding a countdown for the time left (if something does happen after 20 minutes, I didn't play that long) would have increased the tension, maybe with a ticking clock and bell sound every minute or something. The premise was very interesting, and could probably have been used to greater effect. Maybe having the gas seeping in visually, or if the player interacts with it their vision is distorted or they see something creepy? Overall I liked it, very quirky and with good sound design, but with a few improvements that could be made. Good job!