Excellent advice above. Adding the legal framework: if you're over 40, the Older Workers Benefit Protection Act (OWBPA) requires specific language in the release for it to be valid. Many companies' standard severance agreements don't comply, which gives you leverage.
Also: review what you're being asked to release. General releases that waive "all claims" may include things you don't want to give up — wage claims, ERISA benefits, workers' comp rights, or whistleblower protections. Some of these can't be waived at all (e.g., FLSA claims without DOL or court approval).
If you have any potential legal claims (discrimination, retaliation, unpaid wages), those claims are your bargaining chips. Don't release them without adequate compensation.