They both deal with the psychological horror of modern living but in very different ways. Severance is about drowning in a corporate job and the company having total control over your life. Backrooms is about finding sense and meaning in an environment designed to be sanitized and creatively empty. Also while Severance is more of a hard sci fi that's fairly grounded in reality, Backrooms presents an alternate version of reality.

Severance owes a lot of it's visuals to the original Backrooms content.