I really do like analyzing the games I've played and looking for inspiration in the mechanics. Most of the time, the insights are fairly minor - for example, the only thing I'm gaining from the RPG I'm playing on the DS at the moment is that it might be fun to equip catchphrases rather than weapons and armor.
But sometimes you unearth a vast labyrinth of unexplored gameplay caves.
I've more or less finished with Dragon's Dogma. A variety of reasons mean I didn't get more than 20 hours in, but I enjoyed those 20 hours. And there was one part that I didn't enjoy, but I really wanted to.
In Dogma, many of the enemies you fight are quite large. Not truly huge - these monsters aren't walking landscapes like in Shadow of the Colossus - but between five and ten meters.
These monsters are large enough that they have multiple hit locations. You can climb on them, shoot projectiles at them, and so on.
This isn't quite the same as the "climb to strike its weak point" that I'd seen before. It's much more fluid. Let me see if I can give an example:
I was fighting a cyclops, the first tier of giant creature. I was trying to hit its head, thinking "yeah, that's gonna be the weak spot." Fireballs weren't doing much - I was having a hard time hitting the head, since the aiming controls use the same thumb as the firing controls. So I switched over to using lightning, which comes from the sky. But I missed with that and struck its arm - and it dropped its club. Cool!
Later on, with my melee character, I began fighting ogres, the second tier of giant creatures (the tier where the whole thing falls apart, but more on that later). There are a bunch of nice details here: ogres can grab characters and run off to finish them solo, but you can interfere by blasting their arms. You can climb on them, but they do this cool back-flop where you have to jump off quick, but then you can jump right on their heads. Moreover, you can use terrain to your advantage, standing on a small cliff such that their head is at the height of your basic swing and the hit zones for their attack are all below your feet (unrealistic!).
Now, this whole thing was a really interesting idea, and much more entertaining than simply killing orcs. But I think there's a lot more potential hiding underneath.
In the past, I've been thinking mostly of "terrain bosses" - that is, monsters so large that you have to navigate them in order to fight them. But I think that it may be worth considering monsters of the middle size: monsters that you can climb on, or whack at their knees if you don't want to climb on them, or shoot fireballs at their various limbs for different effects. The maximum size here is such that an archer firing at them would not automatically target a limb. IE, a giant dragon where the archer would default to the huge head coming at him is too big.
Having large but not titanic enemies allows you to suddenly have a lot more combat options than you used to have. Do you target their legs? Arms? Head? Do you smash their toes while staying away from their swinging hands and biting head? Do you leap on and climb so that you can get a good hit against a specific part of them? Do you use the terrain to hide, trip them up, or get above them?
You can even bring in team tactics: can you lure it to chase you into a doorway, getting it stuck and letting your teammates jump off the roof of the building onto its back?
The wafting scent of this kind of combat filled my nose as I played Dragon's Dogma, but it never materialized. There were a few reasons for this.
1) The NPC allies are too incompetent. They don't understand to hit the arms of the ogre to get it to drop whoever it is clutching, so if it is clutching you, you might as well reset the game. They don't understand to aim for the head. And they don't move very aggressively even at the best of times, and prefer to try to go toe-to-toe with the enemy. Why?
2) The enemy hit locations are not reactive enough. The cyclops was great: it had tusks you could knock off, an eye you could blind, a club you could knock away. But that was the apex. Every other enemy made little distinction between you attacking it in the leg, the arm, the head. Now, they did have reactive behavior - getting scared and cowering, or falling over stunned, or going berserk. Those were great, but I really wanted to smash its kneecap to slow it down
2a) Note: glowy weak spots are not reactive enough. There is a rock golem where you have to hit glowy weak spots. It's interesting for about five seconds. It would have been fine if those weak spots took less than five seconds to destroy each, but instead they took thirty seconds of continuous onslaught. Boring.
2b) Having limbs you can hack off, like the manticore's heads, is fun... but the manticore spams the attacks with all those heads, making it impossible to tell what's going on. Generally, I recommend that dealing damage to critical locations should reduce the capabilities of the monster and change its attack pattern, but the monster shouldn't have so many chaotic attacks that you can't tell what's going on.
3) The enemies are too tough. Jumping onto its head and stabbing it in the face accomplishes almost nothing. You have to just cling there and hit it over and over. Literally for a full minute, just cling there and smash smash smash smash smash smash... it'd be much cooler if there were more of them, but they were frailer, so that smashing them in the head really had an effect. Stunning them, bringing them down - then the question is whether you can finish them off before the two others get to you...
4) The enemies are too brutal. Even as a melee class, there are times when a single hit will do more than 70% of my max health in damage. There is no "retry this battle": if you lose, you go back to the last save point, which is a huge burden. If the enemies were less lethal or the game punished losing less, it'd be a lot more fun.
5) The climbing mechanic is too clumsy. Dozens of times it would malfunction. For example, grabbing a thigh and pressing "up" on the joystick. I want to climb. But instead, the hero simply crawls in circles around the knee until the giant kills me. Fantastic. Or another time, when my hero inexplicably decided to grab onto the end of the fist, just to make sure any given hit would kill me instantly.
6) Terrain was not used purposefully. I didn't even realize how cool terrain could make these fights until I fought an ogre up and down an ogre-height broken cliff. The poor programming of the ogre made this interesting - it couldn't simply punch me against the cliff I was standing amongst, because it only understood a few moves, and they were all either "attack the ground" or "grab something that's climbing me". The idea of "that guy is standing at shoulder height" confused the hell out of it.
A smarter ogre would have made that battle significantly more brutal, but the same basic idea could have made these combats more interesting in general. Lure the ogre into a ravine. Dance around a crowded forest with him having to uproot trees to get to you. Jump from crumbling fortifications onto its back...
So... could you make a game out of this?
The game would need:
0) The ability to move, and to attack different parts of different monsters.
1) Competent NPCs or multiplayer.
2) Monsters that change their attack pattern and stats based on what parts of them you destroy/injure.
3) Parts of them you can destroy/injure without having to spend all day whacking at it. Instead, allow for multiple monsters.
4) Don't punish getting hit too severely, because it makes the game un-fun.
5) A graceful climbing mechanic that supports easily moving from limb to limb, part to part. Also supports leaping on from other places. The monster may, of course, decide to snatch you up...
6) Terrain which can be used to screw with the relative height of the monster and its mobility, and perhaps even used to get it stuck, cause damage, etc.