Severance agreement arrived, need a second opinion - 4 months and counting

I was offered 4 weeks of severance after 4 years as a web developer, and I have a few days to sign. There are 4 people counting on me, so I am trying to be careful. There is a non-disparagement clause. Did anyone negotiate and succeed?

Thanks for writing this out. I went through something close to it 4 months ago, and it got easier once I kept a simple log of every call and form.