Oddhermit: I can't imagine insane mode being fun when you can die through no fault of your own at several points in the game, or at any time really when your signs or block fail to respond to key presses.
RageGT: We learn how to deal with it and there is no place we can die through no fault of our own! Rushing thru Act 1 now to face that thing that killed me this morning. But now I know what I did wrong! =)
When certain abilities simply don't respond to key presses at times, yes, you can die through no fault of your own.
Although I suppose you could complete the game without relying on offensive/utility signs or blocking and just keeping quen up and rolling around throwing bombs and daggers - don't think it'd be fun to do so however.
On second thought though, even then your controls will sometimes stop responding if you try to use bombs/daggers when you're out of them but they still display in your pockets. So yeah...there's that.
I'm sure a lot of people will claim to have done it and a few will be telling the truth, but it's seems like a meaningless achievement when the only way to do it is to use a ton of cheese and play in a very boring way.