
I like the Adaptation system itself. Having different biological adaptations for pressure, digestion, etc. fits the survival concept of Subnautica very well.
What feels strange to me is how the player acquires them.
Simply interacting with an organism on the planet and suddenly receiving a complex biological adaptation feels almost magical. It makes the system feel disconnected from the scientific survival fantasy that makes Subnautica so interesting.
I think Adaptations would be much more satisfying if the player had to discover and develop them.
For example, the player could collect biological samples, analyze them, discover useful genetic properties and eventually create a treatment or biological procedure that gives the desired adaptation.
That would make Adaptations feel like an actual scientific discovery made by the player rather than a mysterious power obtained from an organism.
The adaptation itself can stay exactly as it is. I mainly think the way we discover and obtain it should be redesigned.

I like this idea; make us scientists and biologists.
Possibly, the character could ‘train’ or spend time with creatures to become proficient with a trait that creatures uses or displays.
Befriend a little bioluminescent fish to follow you around and teaches you to glow - or maybe - deaths by self-imploding fish are more likely to reprint you with a thicker hide.
Sneak up on a camouflage creature?-harvest the mucous membrane for samples and do some science baby.
Maybe you’ve captured a critter and ‘cooked’ it , ingesting it gives horrible worms and floods of unstable compounds, but now you can use an active ability.
Get creative with it. I’ve played enough roguelikes to know I enjoy gaining something from dying besides knowledge.

Yeah, I actually really like the direction you’re describing here.
It fits the lore extremely well, because the player is basically a scientist and explorer studying an alien ecosystem. So I think adaptations should probably feel much more like the result of observation, experimentation and biological research rather than simply being something you obtain by interacting with some strange organic object.
That’s actually one of my biggest problems with the current adaptation system. Right now, a lot of it feels like: find an adaptation source, put your hand into it, and suddenly you get a new biological ability. Even when the system is presented as something scientific or biological, the actual interaction doesn’t really communicate that.
There are also adaptations associated with diseased creatures, where you essentially stun the creature, interact with it, and obtain the adaptation. Again, the idea itself isn’t bad, but the process feels very simplified compared to what the game is trying to make you believe you’re doing.
And that’s what bothers me most about the system: they built an entire mechanic and interface around adaptations, but the actual gameplay loop behind it feels surprisingly shallow. It feels more like a way to add some extra content than a fully developed scientific/biological system.
I think your examples are much more interesting because they create an actual connection between the creature and the adaptation. Studying how a creature works, observing a behavior, collecting biological samples, experimenting with them, cooking or processing something, testing the result, or even learning something by interacting with the creature itself would make the adaptations feel much more earned.
I especially like the idea that the player could discover abilities by actually understanding the biology behind them, rather than simply receiving them from a predefined adaptation node.
That would also fit the game’s identity much better: you’re not just collecting powers, you’re studying an ecosystem and learning how to adapt to it.