Coup de Grace

Hello!

To answer your first question, I feel as though the third and fourth lines could be separated at a different word. To me it seems choppy though I am unsure with how I would change it. When I read it I stop on 'of' naturally since it is the end of the line and it seems to break the flow to 'our'. The rest of the lines seem to be fine. The two long lines, the second and last, are balanced out and do not appear out of place to me.
I feel as though the idea is well communicated, though what I originally got from it differed from what your quote states but now, after rereading it, I understand. For the average reader I feel as though it might be too hard to find, however. The shortness of the piece packs so much into it. I think it depends on who your audience is whether or not you should elongate the piece: if you want every person to understand it, perhaps. But if you want people who have experience in poetry to be able to understand it I feel as though the length as it stands is sufficient.
I love the word choice of your adjectives. You keep them simple and commonplace (this reminds me of Robert Frost's The Path Not Taken) yet when you reach the final line, I feel that solitary (while it is still somewhat common) has a great affect and stands out. Solitary nightmare is a phrase I believe I have never heard before yet, upon thinking about it, I have to wonder why. For verb choice, 'is' in the first line is one of the most plain verbs to use on this Earth yet I have no idea what else you would use. It seems to flow, however, so I would keep it. The other verbs are ordinary yet are not bad and make sense. Illustrated, on the other hand, sticks out and again serves to make the last line pop. I almost feel as though the word choice for the adjectives and verbs starts out simple but ends sophisticated and to me creates a nice affect. Finally, the nouns seem to fit well as well. The nouns remain strong and varied throughout the entire piece, though you also have simple and complex ones paired up. 'Life' and 'hypocrisy' and 'slaughterhouse' and 'history and death' work well. The combination prevents the piece from seeming too full of 'big words', which can be a turn off when they start to pile up and make the poem less coherent. 'End', though, seems like a bland word that could be changed. I am not sure whether you were trying to be simplistic with your word choice in that line but I feel that 'end' could be easily substituted for a better word. Other than that everything else seems to have great word choice.
I feel as though the speaker is an old, wise man smoking on a pipe and telling this with a foreboding look to his children. If someone normal seriously said this, I'd almost have to imagine it being in response to someone speaking about either how man is flawless or how people never listen to the past. I really don't think anyone could have come up with this on the spot, however, and I feel as though it would need to be memorized and quoted.
If someone said this to me I would probably be a bit dumbfounded since the piece is too complex (for me) to understand in full after hearing it only one time. But from what I got from the first time reading it, I'd probably say something about how it's a tragedy that man repeats past errors out of ignorance.
All in all I feel that this is a very well written work and I like the simplicity of it. While a few minor things could be changed, the piece is one of the better poems I have read over the past few days/weeks. However, the complexity of the ideas being discussed may still be too complex for some and I feel as though this could be a hindrance for normal people (I still have to wonder if I have grasped at the specific meaning since I feel that the piece could technically have many). I wish you luck with editing this (if you choose to) and writing future pieces.

This is my first critique and it may not be too good but I hope you got something valuable out of this.