Flawless is interesting.

It can't work in the general case because replaying a sequence of syscalls is not sufficient to put the machine back in the same state as it was last time. E.g. second time around open behaves differently so you need to follow the error handling.

However sometimes that approach would work. I wonder how wide the area of effective application is. It might be wide enough to be very useful. The all or nothing database transaction model fits it well.