Greater level of sickness?

I've just started to play with VR in Unity and realized that I have much greater level of nausea than in games like Euro Truck Simulator 2. I can spend an hour inside ETS2 and it's okay (may be just little unpleasant feeling) but in Unity (with default settings at least) I play for 2 minutes and then have to rest for 20 minutes.

I just wanna know is it only for me, or someone else have noticed that difference?