In the video you’ve provided, there are no visual execution, it’s mostly blackouts followed my sound audios. If your execution were to not contain any form of decapitation, blood, and just generally gore you should be fine.
Can you elaborate on “You can only see them die”? How are they dying and what form of visuals are you planning to provide? The video blacks everything out and then plays an audio clip, is your plan similar to that?
Is there blood when you shoot them? The thing with the video is that there is no actual scene with the gun being fired, the gun is only present. The audio allows the players to interpret what happened.
That seems alright and I believe that would be allowed. It’d be best if the person aiming the weapon did not fire, however, FPS gun games like phantom forces have a fair bit of blood even when the weapon is fired.