Imagine this: Our character infiltrates some secret STCP facility but unlike in any other delve, enemies here know their ropes in containing far more serious foes than you will ever be, so this becomes high risk/high reward scenario. Before entering said location, the player should be notified that this is a dangerous territory with no save points, scarce resources and an instant death if your vitality reaches zero.
Pros:
+ More reason to improve your vitality(light agility builds seem far more superior rn)
+ Horror potential(game is atmospheric but kinda loses the feeling of desolation when you realize that 99% of enemies mean you no lethal harm whatsoever)
+ Cameo potential(same as you did with trash panda in parlour)
Cons:
- Can be a bit too fundamental(literally rewrites the concept of the immortal protagonist if that's what you are after for)
- May require some tweaks with stealth mode(right now it's press Q to win)
- Requires a lot of effort to implement(experienced players can speedrun current delves in less than 3 minutes)
Alternatively, you could try to implement the hardcore mode with a instant death rule but that doesn't change the fact that current game balancing allows you to keep your vitality at 50% with no worries of engaging in battles(unless it's a boss battle but then again if you use high agility/high evasion rate build it's no problem still).
Anyway, keep up the good work man, I'll try to follow your SubscribeStar page when I have a chance.