Cave

Awesome image!
The wonderful mix of carefully laid out experiments and objects scattered on worktables and shelves makes me think of my minecraft bases, in a good way. I play with a lot of machinery mods, and I always end up frankensteining my nice little house into something like the above image and its predecessor. So thumbsup on making this feel like a mad scientist's den, from a wanna-be mad scientist. XD

Because I know that when people nitpick my best ones it can be a little disheartening/irritating but also extremely helpful, to be clear at the start, the piece is overall extremely well done, definitely DD worthy and one to be proud of! This is just me picking out the couple of minor flaws that keep it from perfection.

Here goes the nitpicking:
I'm bad about letting the perspective drift over the course of a piece myself, so I over-scrutinize the perspective on everything- the barrel in the foreground and the stairs really mess with me, because they don't sync up, but they should be viewed at about the same angle. Its the barrel thats off, judging by the rest of the room's perspective; it should be seen more from above.

The texturing, shading, and brushwork are exquisite. not much to dissect; the metal and stone are particularly well done! The only two things I can suggest here:

Do some material studies of wood and cloth, to get a better handle on partially reflective surfaces. this will up the realism to match your metal and stone...

and play more with atmospheric fog and local value adjustments, similar to what you did with the perfect green corona around the tank canceling out the color and value of the objects behind it, making it stand out. As an example of a place this can be useful, that perspective issue actually had me thinking at first that the stairs were a table for a while because without the right perspective cues, they look like they are all on the same level. Tweaking the highlights and shading to make it clearer that the slats of the staircase were on different levels would help with that.

Like I said, this is just me nitpicking on an excellent piece!