Ehy, thanks for your feedback. Maybe I can decrease the rotation speed. It was ok for me but maybe not for everybody. Maybe I can make an option to let the player choose between different sensitivity values, I'll give it a think. Thanks again for your feedback and for playing the game!
Well, actually after your last comment I went there to have a look and I discovered that as long as I use
Input.GetAxis("Horizontal") I can be assured that it is frame-independent by default so I shouldn't be worried about Time.deltaTime in this case, I can leave it out. I guess the only option here is to have an option menu where the player could set the sensitivity, that should solve the problem, yes a slider in a settings menu would be good.