Not really a fan of it. It's a great idea, but it's not executed to well.
The procedurally generated levels are filled to the brim with both stuff that kills you (not even mentioning how the obstacles blend into the background, just making it more frustrating) and platforms, making the game feel claustrophobic.
I don't see the "intense part" of it, other than the "big scary killer laser thing" that's chasing you as you slog around the for some reason spike infested sci-fi lab.
The execution of the "unique idea" that birthed this game is executed horribly, it doesn't feel like "oh I need to keep track of my breathing and heartbeat" it feels more like "oh no I'm running low on oxygen time to spam Q and E"
My advice? Take notes from "Manual Samuel." It's the exact same thing as this game, but the story is
better different and it's "idea" is executed well an adventure game instead of a plat-former. Emphasis on the breathing mechanic, since you have to take most of your focus off what you're currently doing. The heartbeat/breathing in this game is just too simple.
TL;DR: Make the levels more open, and fix the breathing.