At the end of the day, there are two priorities in game design. One is keeping the player from ending up in a hopeless situation but not actually dead, where their only real choice is to commit suicide or restart from a save. (It's the same reason LucasArts adventure games never let you move on to the next chapter if it required some item from the current one you hadn't picked up yet.) If you do a poor job in one battle, you should be able to redeem yourself by doing well in the next one.
The other priority is ensuring this without making the game feel too easy. Regenerating health is an easy way to accomplish the first, and fail spectacularly at the second. Giving players full health restores at the end of every area isn't much better, but at least it doesn't also turn every battle into a game of reverse whack-a-mole.
Half-Life 2 did an excellent job balancing both. It was unlikely that you would ever complete a difficult section without there being just enough health left over around the corner to keep it from being unreasonable, but not enough to feel like a reset button.
Ironically, I have to dock them points for missing a good opportunity to integrate the HEV suit better into the game world. As it stood, it was just an extension of your health bar that needed a different type of object to regen. Other than that trick it did with the poison headcrabs, which didn't even happen until the second game, it never did anything uniquely useful. The most realistic approach to powered armor in a game, to me, would be something like giving the armor a finite amount of power, having it drain some whenever it has to repair some damage either to itself or to you, and being able to regen using a charging station. None of this "your suit regenerates power out of thin air" nonsense like in
Halo.
The "luck bar" thing reminds me of action movies, where the hero can get in multiple firefights yet never get hit once, because if he did he'd be screwed. It would be a little hard to convey to the player, though, unless the game is explained as actually
being a movie, and some NPC brings up this trope (like some video game version of
The Last Action Hero). And as someone else mentioned, having it tick down when the player
isn't getting hit adds to the confusion; a properly-labeled health bar gets its point across immediately, and even an oddly-named one like Duke Nukem's ego bar makes it clear pretty early on what its function is because it's ticking down whenever you get hit.
There are situations that regenerating health has worked well: namely, when management of resources wouldn't otherwise be part of the game.
Portal and
Mirror's Edge do this perfectly. The former is a first-person puzzle game, and having health at all is just an excuse to keep turrets from being one-hit kills, so suddenly adding a health bar and health pickups would feel like a genre shift. The latter is a parkour platformer where stopping to hunt for pickups would break flow. Since there's so little damage you can take in either one before you die, you can write it off as your body shrugging off minor injuries like in real life (although it does seem a bit hard to swallow in
Portal once several people worth of blood end up splattered on the walls).
Triforceformer said:
In Duke Nukem Forever (This is a bit speculation, but bear with me), health regen would work because it helps the player feel as powerful as Duke is; able to take bullets like they're candy...or some other metaphor. It also helps that the health bar is named an "EGO" bar. Duke Nukem's huge-ass EGO can deflect bullets and lasers, and absorb pipe-bomb explosions. That alone justifies the regenerating health. For me at least.
But it's not like DNF just gave up its exploration factor by going with EGO. Searching around for interactive novelties, executing "bleeding out" enemies, etc, inflates the overall EGO. So rather than searching for health packs to mend your wounds, you find say for example, a "Balls of Steel" pinball machine. If you get the high score, your overall EGO becomes larger so that you'll have a better chance at surviving future encounters. Yes it's still regenerating health, but it's regenerating health that accounts for the lack of depth that would come from just having the system and nothing else.
Pity this is all speculation; that would be a very interesting use of the ego bar. Having it go up whenever he does something cool, like a health bar tied in to the achievement system.
