Carving an entire model from the top down (rather than building it up from parts) is a very different approach to what is usually seen in the modelling world. I take my hat off to you for this. It's a different way of thinking and requires entirely different plans of attack.

I like that you carved out under the crucible to distinguish it from the base, but it would also have been good to do the same (to a lesser extent) where the crucible meets the metal stands. More difficult as you have to keep both sides of the "gap" clean and straight, and therefore would have given you many more points.

The roughness of the concrete bases is a good contrast to the relative (while not perfect) smoothness of the rest of the model.
Equally the contrast of the straight lines of the crucible and it's stands to the molten/solidified spilled material is good.

The idea and overall design is good; especially considering the constraints of the shape you started with to carve from.
However, I wouldn't be me if I didn't have some pointers about realism.
And it's mainly about the spill.
For the crucible to be tipped for normal operation, none of the brown should be there. This means that all the brown is from the spill. However, there is far more volume of material that has spilt from the crucible than has been lost from the crucible, and while some could be explained as it had spilt while being filled, someone would have soon stopped pouring once the leak started.
Also, for it to have flowed all the way under the crucible, it would have had to have been molten for much longer than is apparent from the painting (only the immediate spilling material is glowing and therefore molten).

A couple of things that you could have done.
I understand why you left the plaster all the way underneath, and I wouldn't say to remove any more.
One thing to do could have been to make the crucible's supports look like they can be raised up. This allows you to say that the bulk of what is below the crucible is old, occasional spills that don't get in the way of tipping it.
Either some futuristic pistons in the sides of the stands to show they can raise up, or leaving the tops of them open (rather than the peg in a hole you have) and adding some hook-on points to the crucible to show that it can be lifted out of the stands and this is just a "resting place".

And/or carving the bottom of the crucible into more of a curve, to show it has a domed bottom (it looks a bit more of a flat bottom currently), would also allow for it to be tipped without being raised. Crucibles also tend to have domed bottoms anyway as the curved surface is better to avoiding stuff stuck in the corner.

Also, when painting the spill, make more of it still orange/red hot to show it's still hot enough to flow under the crucible. Additionally, painting yellow/orange cracks about the spill (even to the extremes) to show that it's only the surface that has cooled and therefore it can still creep along.

As to the rest of the painting, the grey streaks on the outside of the crucible are actually a good definition of simple but effective.
The concrete is ok, but would be improved with a second/third pass of a lighter grey dry-brush. There's also some grey on the brown spill, and some brass on the concrete.

And that brings us to the molten material.
Inside the crucible, it's very effective. The hot spots are good, as is the distribution of the cooled surface.
At first I was going to say that the black areas could do with more 3D detailing, but after a bit of research I retract that thought as reality shows that you do just get flat black areas.
I like that you have it lighter by the crack as that is what happens with a flow.
The OSL inside the crucible is actually quite effective in it's subtlety, as the majority black surface would be mostly dim. Your photo at the angle that doesn't show the inside does give the impression of a glow from inside.

Outside, the OSL is not quite as effective, and looks more like a stain rather than a glow. It could do with being brighter nearer to the pouring fluid to really sell the effect. With a black surface, you have a perfect condition to really sell OSL (which doesn't work well on lighter surfaces). Good attempt. I'd like to give more advice on OSL, but I've not really pulled it off satisfactorily myself, so I'll say go and have a look at how Klaus does his OSL.

And finally, something to take forward, and something that'll help with OSL, is to practice on your blending; red/orange/yellow are actually really good colours to practice blending with as the poor coverage that often plaques those of us that want a solid coat of those colours helps when blending them together. Use more layers/steps in the blend with mixtures of the orange, orange/yellow, orange/more yellow, yellow... and you'll get there.

Nice take on the theme, and good carving.

Wood and rusty metal, two of my favourite things in models. Made with sprue, and we all know my feelings about sprue.

Anyway, where to start.
Good effort on the sprue wood texture. I see you've added texture to the ends of some of the pieces, but a little roughing of all of them would be a good thing to keep in mind. I sometimes cut little 'V's out of the ends and sometimes just scratch or poke with something sharp. Also, removing (or softening the edges of) the raised plastic that results from the scratching can help with the look of the wood.

The ladder is good. Clearly a quick job, from salvaged materials, by someone that just wanted a ladder asap and didn't worry about who might fall off it.

As well as Anvildude, you also made me do some research. I'm unsure if the rungs of the ladder are wood (as the material they are made from) or metal (to match the uprights). I checked that the orange of rust can bleed onto wood, and it can. And, as it turns out, a metal ladder can be made with wooden rungs; although rarer than the alternative. So I'll go with this.
The spacing of the rungs is not bad. it can be tempting to model a ladder with larger spaces than make sense in reality. But for the width it's a good spacing, even if it's a bit chunky (that just adds to the lazy builder from before). Realistic ladders at these scales are really flimsy, so chunkier are better for gaming.

The tower's frame is a nice use of sprue. Keeping the roughness adds to the ramshackle appearance. But it could have done with a triangle or two to make it appear stronger. It looks a bit too much like it may fall over.

The sandy base is... sandy. The shapes and swirls do help to break up the surface. I think the sand a crept up the legs a little too far, but better than not at all. The plants are nicely distributed.

The water storage at the top is good. The bands maybe could have had some rivets though.

Good variation in the water and good finish. It's a bit too blue for the scale though. As you said, with deeper water effects on top it may have finished better. I nearly commented about the gaps and possible leaks, but it appears you have learnt that lesson the hard way.
You could have added some patches (metal plates etc.) to the gaps to help with the leaky look and real-life issues with the water effects.

However, when you can't see the water, the whole model is a bit too brown. I could have done with something with a splash of colour on to liven it up; some graffiti or posters, a flag, etc.
Also, the plants could have done with a bit more variation in colour. Doesn't have to involve green, as that doesn't seem to fit the setting, just some variation or patches of brown to "bone".

The painting though, is good. The rusty metal is nice and the wood has some nice variations, and it's good that the platform is a different colour/wood from the "tank".
Good job, especially considering you started on one model and then changed to this part way through.

And Tek returns with another lovely design. I do like the clean lines and the gentle curve of the tower's legs. I would have liked some more smaller details though (there's a distinct lack of rivets on something constructed of metal, or even modelled welds).

I like how you incorporated the battery, it's wires and the switch into the model, rather than hiding them completely. Making a windmill with a working fan is a good choice too. I like the steps up to the switch to make it an in-universe lever, and I can forgive the slightly scale-breaking size of it (there's not a lot that can be done about it really), but I feel that some added details about there would help; I just don't know what. The lever looks lonely.

The base is nice. Good scattering and variety in the plants (perhaps only helped by some brown or "bone" dry-brushing of some patches).
The mud is good, nice texture. Maybe could do with an occasional large rock to break up the surface and add variety amongst the plants (that do a good job of breaking up the surface themselves).

The tower is a nice colour. Good depth and variety of tones. But really calls out for something to add a touch of contrasting colour above the green on the base. A sign or two, some graffiti, warning markings (don't go beyond this line unless you want to be chopped up), painting the wires a contrasting colour, whatever fits your setting.
Even, a flag to show wind direction. Made from something light, like tissue paper, so that it actually flaps in the fan's breeze would have been cool. Not very durable, but cool.

Lastly, the water. Is really good. Shows the flow nicely; especially from the pipe. Maybe only missing some splashes where it meets the ground, but otherwise great.

Nice piece. Different in that chaos-y / Ork-y way.
Good design. Has enough of a story to say this has a purpose (what that purpose is, is on a need to know basis).

The base is very nice. The mud looks like it should, and the placement of the rocks (which look like rocks) gives the impression they have been placed on purpose in-universe. Good variation in tones. Only thing I would add is maybe a couple of small tufts of grass growing between a couple of rocks.

Wooden poles are nice. I like the addition of the notches in them.
The string is just about different enough in colour from the wood. But only just.
The metal bits are a nice use of sprue and good way to make use of the shapes, and good on you for adding a rivet/bolt to be holding the cross-pieces to the wooden poles.
Skulls add to the flavour of the piece.

Good use of chains, although one (where the blood is leaking out) doesn't quite seem taught enough at the bottom; a minor niggle.
I'm not sure what the white is on one of the other chains where it meets the central rock thing; it looks like glue that's not been tidied up. Could have done with tidying (if it is just glue), or something to cover it up and give it an identity (like another splash of blood). Difficult to tell from the photo.

And that brings us to the suspended rock. Looks like rock. Nice addition of the metal bands (with rivets).
The blood is red, check. I was going to knock a point off for the bubbles, but you mentioned that you liked the effect. The shrinkage is a problem though. We've already talked about it, but the high meniscus around the edges does spoil the fluid effect.
We've already mentioned adding the glue mixture you used in multiple thin layers, but other things that can be done is to keep an eye on the "liquid" as it dries and as the shrinkage becomes apparent to poke the meniscus down to the level of the liquid (I did this on my CD City too). This avoids the "bowl" effect. Also, painting the raised edges of the "blood" in a dried blood brown colour would give the impression that the high meniscus is old blood, congealed to the sides and therefore not part of the liquid that has shrunk; would probably need roughing up a little though.

And one last thing, not a critique, you could have added a drip to the spilt blood trail. This can be done with a short length of clear thread (or similar material) and running your water effects mixture of choice down it to form a drop at the end. This is sometimes over-done on models that are swinging axes and the like, but a subtle drop in this case would be a nice touch.

Good job. Nice painting.

A fun piece with lots to look at. Good effort.

The base is nice (my Mum even commented that she liked it). Good job on the bricks and I like that you have the larger slabs on one side to make it less uniform. A couple of things; Some sand, brushed into the gaps would really add to the realism (the gaps just look a little too deep). And plants (because you'll all think I'm ill if I don't mention plantlife); just a couple of tufts of grass growing out the cracks.

Nice job on the skip. Good build; could almost be mistaken for a bought resin cast (although there is one wonky bit). Good effort on the painting; grubby, worn paint. Patches of rust. All good. Ironically, I think the graffiti could be a little neater/sharper. Or even add some paint runs from the lower edge of some letters and drips on the ground to emphasise the sloppy nature of the graffiti artist. Study Cam's tutorial and you can take it to the next level.

There's a nice selection of junk inside.
The rusty metal is pretty good. Look at adding some more colours to your rust layers and try a wet surface to help the blobs of paint to bleed out a little, softening their edges.
The planks of wood are very good. Nice work on painting the grain. But why someone would throw out such nice pieces of wood, I don't know. Maybe beat them up a little, splinter the ends, crack the middle, or add some chipped/worn paint to them.
The bricks are pretty effective. Add some texture to them by putting the wooden pieces in a bag, with some rocks, and chuck it about the place. and/or add a little fine sand to the paint for them to give them that rough, brick-y texture.

Good job building the hydrant. Works really well. Could do with some (more) highlights on the red to pick out the edges.
The water is reasonably good. The cloudiness highlights the downside of using PVA, if you want clear water. However, with the pressure and turbidity of the water squirting from a hydrant, it works. Adding some white dry-brushing and maybe roughing up the surface beforehand would show the spray of water (in this case) better. The pooling on the ground is good as is.

And then we have the ex-zombie dog. Being that it no longer looks like a zombie means you did a good job with the GS (would have liked to have seen wip of what you had to start with and what you did to fix it). The colouring is good. Maybe could have had another lighter highlight and been slightly less shiny.
It's "flow" onto the skip is pretty good where it's pooling. The jet that's coming out of the dog, let's just say I'm surprised it's not taken off yet. slightly thinner would have worked better.

Good job.

Nice looking piece. Fair amount of things going on.

The wood is nice (would have been more points if it had been scratch-built). Good variation in tones. I'm not really sold on the bleached edges though; it's a bit too stark a contrast and too uniform about the outer edge.
If it's due to splashes of the "water", then it'd be a lot more random and splashed about, also with possible trails where it's been walked about.
If it's due to gasses given off by the "water", then it'd also show up around the holes and possibly between some of the planks.
In both those cases it'd be less apparent on the upper platform.
If it's just to show aging of the wood, drying out on the exposed edges, it would be much more subtle and again would show up around the holes and edges of individual planks (to a lesser extent).
It is nicely blended, just a touch too stark for me.

The scattered bones would benefit from a brown wash for shading and a lighter highlight or two. Or a black/grey wash and white highlights to show older, bleached bones.
I like the netting/mesh. Good job on adding the strips and rivets and the red cross.
The scene inside is good. Don't really get a great view of the doctor himself to say much. The table looks good with the OSL and blood, and the lighting widget looks suitably 40K.
The fire on top is nice, light works well with the cotton wool.

I really like the collapsed chimney. Looks great. Nicely painted. I like the chipped and crumbling exterior. As I said to Vik, the bricks could do with some added texture by roughing them up a little.

I know you planned to add more to the wooden platform and I'll suggest some things.
Storage; piles of boxes, a locker, etc. would give it a more settled/permanent look.
Some way to get on to the platform; I'm sure no one would want to wade out to it through the pretty green "water". Either a walkway/some planks from the rocks to the platform, or somewhere that looks obviously like a boat can be moored up, or even a boat (tricky to add now the water is on).
Perhaps somewhere for the doctor to rest occasionally; a bed/sleeping bag/mattress or some chairs and a table. More furniture basically.

Good use of cork for the rocks. Always an effective method. I like that you blended them out to the far corner, but I do always wonder where these layers of rock come from when I see piles like this. It's not a natural formation. The individual pieces could do with a bit more blending together (like you have to the corner of the base) to show the layers emerging from the ground, rather than looking like they have been piled up. There's also a couple of unnatural straight edges I can spot.
However, this can be made to work if you sell it with an in-universe excuse; the layers of rock have been placed there on purpose. But you need to show this in the model; maybe have more unnatural straight edges, add some "chalk" markings to show they've been measured and cut. Some track marks from a JCB-alike, or even add the digger/bulldozer. Or just a collection of men-at-work props such as spades and hard hats.
The colours and tones of the rocky ground is nice too. Good variation.

The piece of wall, advert board, and glowing wires/pipes. are painted nicely, good colours and weathering. What they lack is a purpose, the wall and wires in particular (an advert board can pop up anywhere).
I'm all for added details to a model, but I like them to have a reason to be there, not just added for the sake of it.
The advert is fine, I like that. But how old is it? It's clearly since the Emp'or, but that still spans ~10000 years or so. Your doctor doesn't really look the Imperial type (I could be wrong), so it's not really advertising to him or his clientele. Maybe someone would have defaced it in the intervening years; a bit of graffiti maybe. Not absolutely necessary, just an option.

The wall is a bit conspicuous in it's presence without any "friends". It could do with some story to tell why it's there. You could show this by adding some more scattered chunks about; maybe even mixing them in with the earlier piled rocks and workmen I mentioned. Having some near the water pipe (which I'll come to in a bit) in the other corner to link them together. Something to show that the fancy buildings have fallen and been replaced with green "water" and wooden shacks (the defaced adverts also add to this).

Then there's the green, glowing wires/pipes. The OSL is nicely done. But why is it there? Where's it come from and where's it going? Why does it snake out of the piled (or natural) rocks? What does it do? It really needs a purpose, and the fact it's glowing so brightly means it sticks out on the model, grabs attention, but only leaves questions.
Possible uses; maybe add some jury-rigged wires to it, leading to the wooden shack as if the doctor has dug up the wire (would need to show the digging) and has tapped into it to power his surgery.

And now, the water pipe. Good job on the aged brass. There's a nice variation in the base brass colour with darker patches and dusty patches. Don't get too carried away with the verdigris paint though, it doesn't have to be all over. You are nearly there, it's only a few spots where a little less would be more; e.g. the outer side, Eagle thing, halfway up; above the lower wing, the paint has bled a little too high. Verdigris tends to form strongest in sheltered spots, under, not over something.
Also, does the whole tube and everything on the tube have to be brass? This is more important than the Verdigris, as making select items not brass will lessen the impact of all the green-y-grey-ness. The Eagles could have been golden, the hatch could have been steel, and the fan and it's housing could have been any colour. These would have all helped (with the poster I see you added) to break up the mass of brass.
And it looks like you forgot to paint the support post, it's still black with the spray of the underwater area on it. This would have been ideal to paint to match the scrap of wall on the other corner of the base to tie these together, as mentioned earlier.

The flow of "water" coming out the pipe is good and the bulk "water" is very nice (My Mum liked it too). The painting under it works very well and the bubbles, while not ideal for all circumstances, works for this setting. Vibrations/tapping on the base of the model can help get bubbles out of poured resins like this, should you want to do something with less bubbles next time.
Probably could have done with a bit more splash where the flow meets the surface, possibly with some highlighting dry-brushed on to show off the texture and show the splash.

Nice looking piece.