Not quite a gun but close.

...Luckey said he turned to a more rudimentary but no less horrifying method of three explosive charges he usually uses “for a different project” (which he did not elaborate on) attached to the headset essentially like gun barrels. The charges are connected to a photo sensor that detects when the headset’s screen flashes red at a certain frequency during a “game over” display. Once that happens, “the charges fire, instantly destroying the brain of the user.”

The visuals remind me of that homemade suicide helmet that used a bunch of shotgun shells. That thing creeps me out from the amount of conscious effort the person put into building a device to end their life, it wasn't a spur of the moment thing.