For some employers I've even supported customers after I left. I've even sent potential customers their way. I work in a small field, we all know each other. But in my line of work we're all in one year contracts and they are rarely renewed, although I had one string of nine years.
Its usually good NOT to burn bridges. If you stay in the same field, you probably will encounter some one from the company again.
I've had a few narcissistic managers make it clear you should never come back. About 20% of PhD level management in technical fields are afflicted with that sort of problem. They would bad mouth a Saintly 30 year employee just for leaving the company or retiring.
I also find many co-workers who are close friends at work, drop you like a hot potato when you leave.
I do know if a company needs my time 24-7 and on Christmas, and if the boss even calls me on days off, that is a big warning sign that they are not hiring, and/or training enough employees. I learned that at the last employer.
Without knowing your situation, it is tough to make a call.
So if last two weeks pay is not there, I'd be calling the State. Did they also withhold first two weeks pay? If you have to seek un-employment, you may need to document this event to prove you left a hostile employer, depending on the state.
Usually this does not happen with large employers. I now shy away from companies less then 20 employees.
You do owe them compliance with the legal portions of your NDA and returning any company property you may find later. For about one year. Be aware that half the stuff in most NDAs is illegal, especially those terms that deny you employment in your field, so you need them reviewed by a lawyer.
Steve