I absolutely love the little details, like the stitches and the flowing strands of their hair.
At first Harry looks dead, the glassiness in his eyes, but looking at the redness surrounding the stitches, which means infection, shows that Harry is alive. The same with the blood on the thread that goes to the needle.
In some areas there is the redness of the infection and open sore-like stitches, but there is also places where there is no redness, like on his face and parts of his thighs, which goes to show how long Snape has been doing this.
Then there is the look on Snape's face as he looks towards his creation, Harry. he looks so satisfied, so pleased with himself in this torture.
Also, I noticed that Harry doesn't have nipples. And has a bit of a chest.
Is this not a torture, but an actual Frankenstein-like building of a body of parts?
Either way, this is brilliant, beautiful, and deeply disturbing. Love it.