I was playing Asphalt 8 and NOVA 3 today and the screen just turns off like it was not in use. Is there any settings to let it stay on while playing these games?
If you didn't touch it for some time (enough for the screen to time out), that may be the issue. Set the screen timeout to something higher.
On the other hand, if you were sure the above didn't happen, it may be either a hardware issue or the fact that the phone heated up so much, it turned the screen off!