I recently quit a great paying job at a large company. I did it to move across the country to find better opportunities, as well as better weather.
I told recruiters what pay I expected at the current role and not what I was previously getting. What I was looking for was $10k less than that previous job. If a recruiter pressed me on my previous compensation, I told them and continued on to say that I didn't want to miss a great opportunity simply because of a wage difference.
As far as reasons for leaving, I said I wanted to work on a different project, as well as mentioning the climate change. Don't lie to the recruiters, because they will find out or guess one way or another, but make sure to tell them something that will essentially distract them from a possible negative in why you are leaving. Stating that you are looking for a better work-life balance comes off as both a negative and positive (which most recruiters will understand), but stating that you don't want to continue working 60-80 hours a week comes off as negative. It's taken as criticism of the company as well as them wondering why it took you 60-80 hours to get your job complete. Some recruiters will understand it's the company dumping too much on their employees, and some will think you are just a lazy/slow worker. They forget that slow/lazy workers don't spend 60-80 hours at work.
As Borgh mentioned, you are a pro. Getting hired at one of these companies is tough. The fact that you got in there at all shows how good you are. Just because you couldn't keep up with the uber-OCD or hyperactive people they like, it doesn't mean you are bad at your job. What it does mean is that you are more normal than their average employee and not willing to literally kill yourself to make others rich. This is a good thing. The fact that you even tried to work for one of these companies shows that you are willing to work hard and are more than likely to be a high performer at any other company. I have a friend that used to work at what was essentially a technical sweatshop. He is much happier in a different job. He also felt like a failure after leaving the job, but eventually realized his worth as well as the unrealistic expectations of that former position.
It might feel like a failure, but failure is often just a reminder that you aren't ready for that task and there are always more options to keep trying. Feeling bad for a while is natural. Getting fired hurts, even when it's for the best, including maintaining your sanity. Just try to realize it was their unrealistic expectations that got you fired, not anything you did. If they hadn't fired you, you'd shortly be burnt out and worth less to other companies. Not worthless, just less inclined to work hard for someone else after such a bad experience. Been there, done that.
Take your time to make sure your next position has realistic expectations. Since you have some money in hand and on the way, you don't have to jump at the next job and simply hope it's better. Take some time and make sure you actually want to be there.