I'm about to do level 1 right now... come join me!
DO take a break if you need to, just not a long one. I noticed a HUGE difference in just a couple of weeks doing the video a few times a week in my posture and my chest has moved UP a couple of inches. No more sagging.
It's hard, just modify what you need to. For example, the last ab sequence (the bicycle crunches) were too tough for me at the beginning, so I just lifted my legs and bend them at a 45 degree angle. They get easier almost instantly.
Ok, let's get started!