This was a bit embarrassing. I stumbled across it while looking for a short film to watch, and assumed it was a student film of some kind that ended up on Letterboxd and IMDb somehow, but nope. It was directed by Shozin Fukui, and while he's no Steven Spielberg in terms of name recognition, he's made a fair few extreme cult horror movies/shorts in his time. He should've known better than to think this was good enough.
S-94 understands gas masks are creepy, and good on it for that, because gas masks are creepy, especially in black-and-white, for some reason. But that, plus a grisly scene right near the end (complete with an admittedly terrifying use of sound) is all it has to offer as far as horror goes, and if you want to judge it as a sci-fi/dystopian film, it offers even less. It's woeful. Part of that might come down to the wonky English subtitles found in the YouTube upload of this, but I think some of it was just poor storytelling.
One creepy visual reused over again and some nonsensical (yet visceral) violence near the end does not a good short film make. All those things do is keep S-94 from being absolute trash. At least this was only about 29 minutes in total, but I still think that might've been about 25 minutes too long, in terms of what they had here that actually worked, or came close to working.