[LukeShu]

I think the only upper/lower case issue I have is with K--I think the other letters are fine.

About the colon: In many cases in typesetting, shifting the colon to the left looks better, but not always. In TeX, there's ':' for ordinary colon and \colon for the left-shifted colon. Anyway, I guess it isn't a totally absurd choice if they're really trying to target a use other than code.

I agree about $/S.

I'm not sure what you're seeing with the vertical alignment of [], they look fine to me.

More criticisms as a code font:

At the size I'd be using for code, ` is nearly indistinguishable from '.

At the size I'd be using for code, @ is just an odd circle-ish glyph (though I love it at larger sizes). And at small sizes it can be hard or impossible to distinguish it from © (I don't think you have ©, I think it's falling back to a different font).