I like the green of the duvet for sure - totally a me thing but it seems like the accent walls chop up the room,

would he open to a light khaki? we had BM revere pewter in my son’s room and it aged really well, not too dark and not too light - but you’d need to check it against the carpet

a nice blackout bamboo shade would bring in some warmth and texture - and at least one chunky lamp would help the feel of the room so much :) overhead lights kills the vibe as my kids say…

I would do a dark green like the bedding. Get the posters framed and matted. Replace the light, get a night stand and add a lamp. Move the bed to be along the edge of the window

I'm sure your son has his own ideas but here's a visual of some suggestions. Paint all the wall in a creamy white, look into closet organizers, a bookcase, a larger desk for all his monitors, etc...

You can paint the walls a dark color, but you will need put in a ceiling light that gives off natural light. He can have the twinkle light on a remote for when he wants just those lights on. No need to add a curtain to his closet, it will never be closed 😂 A closet organizer will be a great addition. Then follow what lisedv has suggested.

the green bedding is nice. I would paint the walls the color of the floor and paint the wall behind the monitors black, a soft matte black

Leave the closet door off, and paint all the trim the same color as the wall color, no contrast. a simple bamboo blind, top down/bottom up for neatness and texture.

Fill the ceiling with the twinkle lights.

put the cubes on the entry wall. Is that the best place for the bed?

Thank you all for your ideas! This is incredibly helpful

My teen son is way more int LED lights than twinkle lights.

Love that he knows what he likes. Paint the four walls one of the blacks posted below. The green duvet will be a nice contrast.

Get two torchiere LED lights with dimmers where you can adjust the temp of the light and the direction it is pointing. He will have a lot of flexibility with creating different feels with dimmers and temps.

They make great cllor blocking primers these days so it shouldn’t take too many coats to paint over black after this phase changes.

He's either a budding engineer, or heavy into gaming in a tomb? Whatever or whichever.....midst the crowding, does it matter what paint color: )? Paint it black to match the monitors, and pray he gets a healthy daily dose of sunshine into those still growing bones.

None of my business, but the locked away gaming so rampant these days , does seem a trifle worrisome. Again, NOMB. - feed and water him, and pray lol

lol Engineering is his dream! He prefers twinkle lights over LEDs and is looking for a cozy space to read and talk to friends (real life). He games less than the set up might suggest and plans to remove one monitor. All black walls isn’t being requested and won’t be suggested but lots of great ideas for him to consider here. Thank you thank you thank you!

Paint the ceiling green, too. Add a ceiling fixture which resembles twinkle lighting.

Son's room needs a flush mount, so google and include that it has Dimmer Compatibility: which is necessary for controlling the intensity of the twinkle.

Have teen scroll through some magazines, cut out photos he likes, frame, put on a shelf.

Too soon, your son will be off to live his dream.

Ooooh I love this!!

There are so many ideas on line. If interested, maybe search Pinterest and Houzz (teenage boy dark green bedroom). The more options he sees the easier his decisions will be.