Below, you'll see any text that was highlighted with comments from the reviewer.
Message to Readers
~Horatio's Oath (Unedited, sorry)
~We were once brothers
The inevitable existential crisis that comes just about when you're doing was well-captured, and the element of desperately wanting to have no regrets was present throughout. Also like the possibility of this essentially being one long continuous dream sequence and that Othello may be just hallucinating, given the unsure, ethereal feel to his thoughts.
As someone who has no idea the background behind any of the characters, I have no background as to what happened between them - if you're re-writing Shakespeare, still be sure to include some context? It might also be interesting to provide Iago's perspective to the exact same moment to provide a contrasting attitude. However, since this is what I presume the ending, how you ended it was very effective and provides good closure.
-Maybe try to just stick to one style of grammar - either archaic or modern - as the contrast between the two was rather disorienting.
-Consider a little more description of the scene itself beyond the actual dialogue: physical descriptions, proxemics, etc. that could help to add to the overall melancholic, final feel of the piece.