I think it would be really cool if the screen went black over the course of 30sec-1min after oxygen reserves ran out (in the event life support was turned off/damaged or the canopy was destroyed). Currently, the timer running out just immediately kills the player in a somewhat jarring and arguably unrealistic way.
A recommendation from me would be to reuse the blackout visuals already in the game (from emergency dropping out of SCO or using too aggressive of maneuvers in glide). Using that as a baseline, you could effectively simulate the PC holding their breath, and then their vision going black from lack of oxygen/hypoxia.
Additionally, you could add a side effect that makes controls less responsive as time passes. For example, controls could move more slowly, in uncontrolled directions, or not at all.
These modifications could increase the immersion level of the game and make running out of oxygen much more exciting for the player.
A recommendation from me would be to reuse the blackout visuals already in the game (from emergency dropping out of SCO or using too aggressive of maneuvers in glide). Using that as a baseline, you could effectively simulate the PC holding their breath, and then their vision going black from lack of oxygen/hypoxia.
Additionally, you could add a side effect that makes controls less responsive as time passes. For example, controls could move more slowly, in uncontrolled directions, or not at all.
These modifications could increase the immersion level of the game and make running out of oxygen much more exciting for the player.