Yeah, that’s really poor of you.
Go out and sit in the cafe/foyer if you want to play a game on your phone.
It doesn’t matter if there is just your friends next to you ( who probably wanted to enjoy the film or else why did any of you go?!?) - the light from your phone is distracting to anyone in the cinema who have it in their eye line.
Which is why the cinema asks people to turn off their phone when the film starts. If you didn’t understand why they ask this before then hopefully you do now.
Sorry, it lost my quote - that was to @Jotunn9