Curious if this is healthy for startups in long term, to work like that crazy.

I always worry that i might over-burn the team by doing things like that. After all, startup is more of a marathon than sprint.

I think it really does depend on the company, culture and how it's approached. If you have everyone working towards the same goal and focussing in, I think maybe it can work.

However, I've been on the receiving end of very unrealistic goal setting. It's completely demotivating.

I'm sure there are scenarios where it can and will work, but in my situation it most definitely does not. All I would say is, be careful!