Four is death after all, at least according to Tv Tropes (which will also happily kill your afternoon).
Anyone who was around for most of the NES and SNES era can probably count the number of ways that you could die in a game, even if you had the luxury of a health bar and could take more than one hit. It's a lovely list composed of electric fields, crushing walls, pits filled with lava or nothing at all, and of course the ever popular spikes. Nothing quite captures the frustration of that mistimed jump or slide or shot, we've probably all been there at one point or another.
Here's the rub though, do we still need to be there? And are we even there anymore?
From where I'm standing insta-death hasn't really seen a whole lot of usage anymore, and I'm not sure whether that's a good thing or a bad thing ... I guess that's why I'm writing this now, to try and figure that out. To come to a conclusion though will require some hashing out of the state of things in general.
I believe that insta-death, when it's done right at least, is something that speaks to skill, rather then frustration or luck. That's not to say that dying the ump-teenth trying to run the gauntlet isn't terribly annoying, just that when it's done right and there's a clear link between skill and success that becomes a reward for the effort put in. This goes hand in hand about what I said earlier regarding frustration, because there's almost nothing quite like the feeling of finally overcoming an obstacle which required you to raise your skill level and punished you for not being good enough. You can look back and say "now I am beyond you" and smirk with the satisfaction of a job well done.
At least, that's how things used to be.
These days games are paradoxically more complex and yet also simpler. As I've discussed before game companies have a very express fear that by frustrating the gamer they will lose them as a potential source of revenue. That's why unless a game is marketed as "hardcore" or "super difficult" you're unlikely to find insta-death being used, and even then it almost seems to be tacked on. The advancement of technology has also taken some of the pain out of the old dog's bite: death is rarely more then a slap on the wrist and a short sojourn to the last checkpoint these days. I'm not saying that having a limited stock of lives is better -- those days are long past us and I can't say I'd be fond to see them return -- but I believe that in losing insta-death that we've also taken away an element that is important to games, a sense of actual foreboding.
I think part of the reason that insta-death has gone unused for so long is also because games are longer then ever and also less segmented. Falling into a spike pit worked alright when it was only on one particular level, but when games are placing a whole world in front of you such things become a lot trickier to implement. After all if you die in some part of the world and were wandering around not really paying attention then you're at the mercy of any checkpoint you might have stumbled into, or worse, a reset slate and what might have been a good chunk of progress lost.
I'm not saying that there's no place for the mechanic anymore, just that it must become even more tempered against the new ways that games have found to present themselves. It will be doubtless interesting to see if anyone is up to that task.