I wouldn't say this is your typical yaoi. Yes, it has themes of abuse and violence in it like the larger part of yaoi, but it's different in that it's not smutty in origin. Mature, yes, but not just constructed to arouse the audience.
This manga deals with the issues of power, abuse and resultant human emotion, although it only just barely exposes anything about it because it's a oneshot. The art uses a lot of blacks and whites to create a dark setting, maybe also for symbolism. The characters, which are used to depict a little of the dark of human life, have some dimension.
can't say this manga accomplishes anything significant because it's just a oneshot and all it does is show a sad premise, but I have a feeling the author felt that it was enough to put a dark reality into painting. If it were taken a little farther, he might have been able to communicate some message about life.