Yeah, it can be run windowed. Do note that it'll likely have a rather notable temperature impact on your graphics card to run it windowed (I think the difference for me was around 10C higher while windowed). As long as the temperature doesn't go higher than the 70C range, it should be okay. If it gets higher than that I would recommend not using windowed mode.
"Some men see things as they are and say why. I dream things that never were and say why not." ~ Robert Kennedy