Wow, this one is incredible, I am blown away how it has been made in just 7 days! The atmosphere is perfect, the graphics are mindblowing (I expected nothing less from a game made in UnrealEngine!), and the experience is very well crafted!
Tho I have some critiques, like the fact that oxygen times and resources are very tight. In my first playthrough I've gone straight for the torch, having only the first oxigen tank upgrade, and I essentially softlocked myself, as I couldn't go any further to search for more resources due to the limited oxigen, nor I could search on the surface where I already took all of them.
In my second playthrough I've gone straight for the max oxigen upgrade, and even with that, upgrading to the torch was very hard. I would've liked a mechanic like Subnautica, where if you end up losing all your oxigen, you still have 3-5 seconds to get outside of water to take breath. I've died many times when I was just a few meters away from the surface, and it got extremely frustrating pretty quick.
Beyond this, this game is just perfect! The mechanics are straightforward and well implemented, also a thing that I liked a lot was a fully functional options menu!
By the way, in the ending, I'm almost sure both characters die just because there wasn't realistically enough oxygen to dive so deep and then return back lol