NTR Dungeon of Twisted Common Sense is an easy, enjoyable game without being particularly outstanding.
Story: The story is very bare bones, and pretty much just acts as a way of getting the game started and explaining the mechanic of the two named characters going along with the weirdness of the dungeon. However, I personally thought that the "twisted common sense" affected the male companion as well as the woman was a nice way of keeping the story enjoyable by minimizing the emotional weight and conflict, and making the cucked childhood friend something of an active participant in Sinon's various sexual escapades.
Originality: Not particularly original, this game features a very simple, very classic RPGMaker format, without any novel mechanisms or twists. If you know anything about RPGMaker, you could probably replicate this game without much difficulty.
Art: Personally, I found the art very enjoyable. Sinon's design and costume, with short hair, huge breasts, a phat butt, and a lovely purple outfit, were very appealing to me, and the scene art was quite enjoyable as well. Like the rest of this game, it's not outstanding, but it is enjoyable.
Translation: Quite servicable. I thought that most of the lines sounded quite natural, and i could plausibly imagine a human writing/saying almost everything, as opposed to the word salad of pure MTLs. There were a few points where the text appeared to continue off the screen, but judging by the context, only a portion of a word or a single word was lost, and it was all in unimportant locations. The sex scenes were translated adequately for the scenes to be erotic and enjoyable.
Game length: This is a very short game. I was able to play through it, activating each scene that I could find, in about an hour and fifteen minutes. I made multiple trips back to town to use the heal event, which probably lengthened my playthrough a bit, but I was somewhat disappointed by how short the game was. I found the ending somewhat abrupt and unfulfilling.
This isn't a game that I'll treasure forever or anything, but it was enjoyable, and I recommend it if you'd like to spend an hour watching a cute redhead getting dicked down by various monsters and people.