Hey, this game is really cool! You executed on the one bullet idea suuuper well - it feels very impactful, and it's clearly communicated. I think that a big part of these themes is trying to make the idea into a meaningful piece of gameplay, where "only one" is something your actually thinking about or feeling in the game. You absolutely succeed here!
The levels felt a bit claustrophobic and frustrating to me, but that may just be a preference thing. Overall great job!
Check out our game Einnsámr too! https://itch.io/jam/gmtk-2019/rate/463168