They seem to be gunning for 10 levels.
The slave collar guy is probably holding something in his hands originally. Yeah. It could be a bust. I wonder of who. The masters would not make statues of the slaves, only the slaves would after they were freed.
Keen observation but there could be other explanations. A gargantuan statue of a slave as a piece of propaganda to nail it into everyone's head that the fate of slaves is etched in stone, and displayed as an ever unchanging fact, and anyone could end up being enslaved under the right wrong conditions. Imagine a slave fed up and at his limits, thinking about rebellion or running away and then he looks up and sees the statue. "We went to all the trouble of building this huge thing out of stone and putting it here. Just imagine what further lengths we will go to, to put you in your place should you start being disobedient.".
Then again, it's buried under shit that's ages old and forgotten itself.
But my first thought was that it was some sort of giant or titan captured and literally turned to stone but then again, the iron on his neck would need not be also stone.
At any rate, it's just something that looks cool. I doubt they are giving it as much thought.