Carbon Conservatory

Glass-9 is one of humanity's last botanical refuges, and it is running out of air. Operations calls the shortage an acceptable variance. You are Silvan, a maintenance worker with a fern grown into one arm, sent into the neglected sectors to turn the valves by hand.
The things still tending those sectors are not plants any more. And they shoot first.
Carbon Conservatory is a top-down bullet hell with the bones of a Souls-like: a hand-built world of sealed routes and shortcuts, breathing beds to rest at, bosses that punish carelessness, and one combat verb at its heart. Parry the growth's own fire back into it, and make it bloom.
Parry. Seed. Rupture. Bloom.
Parry — Raise your frond bracer just before a round lands and it flies back carrying a seed. Read the first shot of a burst and the whole burst is yours. Mash it and the window closes.

Seed — Every returned round plants seed in what it hits. Fill a husk and it splits open.

Rupture — A ruptured husk is silenced, stunned and soft. Fail to finish it and it scabs over, harder to open the next time.

Bloom — Kill it while it is open and it bursts, seeding everything around it. Chain the bursts through a squad: pop, pop, pop. The overgrowth left behind seeds your own rounds.

Everything is a gun
Both sides of the fight are armed. Your barrels are living grafts, and every one you find is rolled, with its own grade, rarity and traits. There is no ammunition, only heat. Run the sink hot, then purge it with a quick directional sequence for an overload that hits harder, or fumble it and jam. Dash through the fire on recharging charges. Graze rounds to build adrenaline. Every husk answers with a pattern of its own, and every pattern is telegraphed: you can always see it coming.
A refuge that remembers
Interlocking sectors — overgrown glasshouses, cable galleries, night gardens and stranger places further down, each with its own puzzles and its own staff of husks.

Bosses worth seeking out — every sector has the boss in your way, and harder ones for those who go looking.

Grafts torn from bosses — each one changes how you fight, and opens routes in places you have already been.

Breathing beds, not checkpoints — rest to refill your Dewbuds and wake everything the air feeds. Die, and your pollen waits where you fell.

Puzzles that grow with you — hedges that open and close on a watering rota, a white hare that rewrites its own trail, and locks that only answer to what you have taken from the things that guard them.

Psychedelic botanical horror
Copper machinery furred with moss, glass domes cracked by roots, orchids blooming out of boilers and a dark lit only by what still glows. Your ring companion Mica can model the shortage. Somebody still has to walk into the Allocation Chamber and turn the valve. Best played with a controller.