itch is a Twiny Jam entry, which means that it had a very tight content and word limit. Accordingly, it's pretty short, and within that short space, it does a lot of its storytelling through images rather than through text.
It's also probably the most compact demonstration I've yet seen of the principle that interactive horror works best when the player is deliberately walking into danger. In this case, we are pretty sure that scratching is a bad idea, and yet the temptation to do so is so strong -- tied with curiosity about what's going to happen -- that we're drawn into it anyway.
Without that component, itch would be much less interesting, though the final reveal is the kind of scary-gross-funny thing that could easily turn up in an urban legend. It made me go "ugh" in the moment and then left me with several fridge horror moments afterward. (Spoiler - click to show)If there's an eyeball in my body that I wasn't aware of, can I see out of it? If I can't, WHO OR WHAT CAN??
It's always hard to assign a rating to ultra-short and in some respects unambitious games that nonetheless do exactly what they're trying to accomplish, and I wavered between 3 and 4 stars before settling on 4.
That Sinister Self is a short horror Twine that dramatizes the ways our own minds and self-critical impulses can turn against us. It focuses particularly on the kinds of body-shaming thoughts and social concerns that are common among high school girls, but it's presenting a kind of distorted thinking that can affect other groups too.
It does this with a neat trick of typography: the main text appears right-side up, but underneath is a reflection layer, upside down mirror text that sometimes reads differently, indicating the alternative perspectives of the second, mirror self. As time passes, the mirror text differs more often, more aggressively, demonstrating the warping of the inner monologue. The mirror text makes fun of the protagonist, emphasizes her flaws, rejoices in her mistakes and embarrassments. There's no way to interact with this text, to erase or refute it; we can only take actions in the real world and hope for the best.
There are several endings; I reached only one ((Spoiler - click to show)The Contagion Ending), but it felt sufficiently fitting that I didn't really want to try for others, so left it there.
Speaking purely personally (and this is why I haven't assigned a rating), the emotional impact wasn't as powerful for me as that of some other pieces that delve into inner monologue. (Cis Gaze comes to mind here.) I think this was because the protagonist didn't seem to me quite as uniquely imagined and individual, but more like a representation of a general type of problem, and those usually don't work quite as well for me.
Your mileage may vary, however -- and there was plenty of formally interesting content to make this well worth playing.