Personally, I don't see high lethality as being a bad thing in any rpg setting.
The knowledge that your character can die just as easily at max health as she could at lower health underscores the inherent danger of combat much more so than if the character had 100 hp to burn off before needing to worry about death.
It's especially relevant in a CoC game, where characters are encountering truly menacing creatures; things they probably never should have gone looking for in the first place.
But really, you can use this system for great effect in a modern setting, a futuristic setting and even fantasy settings.
Right now I'm reading about resistance checks, and I'm not sure how well I like those. They seem a bit convoluted to me, but I confess I was reading them at 1 a.m.
The whole skills going over 100% is confusing right now. I'm not sure how you make a check above 100% -again, late reading might be the problem.
I understand how that can increase the chance for heroes to score crits, but it just seems that they are going to succeed at everything they do, so in effect, at that skill level, you are only really rolling to see if there's a fumble or a crit.
Is that correct?