Portal 1/2 has a lot of non-violent levels, but a demented AI is passive-aggressively trying to murder you throughout the game. You may also end up under a laser, a press machine, an oven, at the bottom of an abyss, melt in acid or get riddled with bullets. What really is violence anyway?
Well you never kill biological things, just an artificially intelligent machine at the end.
But also one thing you can do is play the two player co-op mode on Portal 2, which as far as I know is pure puzzle solving.
The stories in Portal are great though, especially Portal 2 which is rich and funny. You could just skip the end of the game and I think that would be pretty non violent? I don’t know if destroying a machine counts as violent.