next »

[runevision]

I'm developing a 2.5D platform game, and I've been working on implementing path-finding to let NPCs (enemies, companions, or other characters in the game) be able to find their way around in the world. For example, this will let them be able to chase/follow the player, or flee away from her.

So far I have a simple proof of concept with multiple red NPCs following the player (but not being quite perfect at it yet):




The game will partly focus on exploration, but there will also be some enemies to defeat. I have yet to figure out and decide what the core combat game mechanics should be.

I want game mechanics that create a focus on using the environment to one's advantage, and which makes use of the maneuverability of the enemies in an interesting way. But which mechanics can create that form of gameplay?

In practically all platform games I've seen, enemies have exceedingly simple movement patterns and a very limited ability to move around in the level. Most often an enemy simply patrols a small path going back and forth or similar. My aim is to develop more engaging enemies that are almost as agile as the player. If anyone knows of existing games that have tackled this problem, I'd like to know!

I want the focus to stay on platforming though and not make it into a combat game. I don't care for twitch or combo based combat, but would prefer a small tactical element instead, using the local environment to one's advantage somehow.

I've thought about the 3 most dominant fighting mechanics in platform games:

• Jumping on enemies' heads
  Like in Mario or Sonic
• Shooting (typically horizontally and vertically only)
  Like in Commander Keen or Cave Story
• Melee
  (I haven't played a lot of those because these often seem to have more focus on combat than I care for)

Early tests quickly revealed that jumping on enemies' heads don't work at all with agile enemies that move fast and unpredictably. All games with this mechanic have enemies that move rather slow or at least in a very predictable pattern.

Melee - I'm not sure how that would work well, as you'd have to always approach the enemies closely, which I think will make it harder to use the environment in an advantageous way.

Shooting from a distance seems like the best candidate to support the kind of gameplay i want, but I'm still not sure how to model the details of the game mechanics to encourage a play style based more on simple tactics than on head-on confrontation.

If you have a platform game where the enemies are agile and not limited to move in a little confined area, how would you design the game mechanics to exploit this in the most interesting way?

Rune

[John Nesky]

The last third of Metroid: Zero Mission has intelligent platformer enemies that follow the player.

http://www.youtube.com/watch?v=dUeybo9QkHE#t=2h8m50s

Technically the enemies are not persistent from one room to the next, but the game keeps track of whether you're being followed, indicated by the flashing red lights.

[agersant]

What about not giving a weapon to the player so that he can only use the environment traps to kill the ennemies ?
Or maybe you could give him some kind of luring (and dodging) ability to help him, but still no way to defeat the ennemies by himself.

[fraxcell]

While not strictly a platformer, the AI in Assassins Creed (both I and II) are pretty good at following you around, even as you climb and jump around on buildings. Most of the time they aren't nearly as fast as you, so you can still avoid them quite easily. I think they will also run away by climbing around on buildings if they think they are outmatched.

[runevision]

The last third of Metroid: Zero Mission has intelligent platformer enemies that follow the player.

http://www.youtube.com/watch?v=dUeybo9QkHE#t=2h8m50s

Interesting. It looks like in some places the player can loose the follower by hiding, and make the follower either give up or proceed forward to where he thinks the player went. I have considered also creating such mechanics, by making enemies know only where they saw the player last and in what direction she was headed at that time.

[runevision]

What about not giving a weapon to the player so that he can only use the environment traps to kill the ennemies?
Or maybe you could give him some kind of luring (and dodging) ability to help him, but still no way to defeat the ennemies by himself.

These are interesting ideas that I have also pondered over myself. The question though is how to make it work exactly. The enemies should be able to avoid traps normally; it would be too easy if their following always ends as soon as the player jumps over/dodges a trap and the enemy then fails to do so.

I guess it could be possible to make the enemies go into an extra aggressive mode when they're sufficiently close to the player, where they are not as careful to avoid traps.

[agersant]

What if you traps where to be activated by the player rather than just laying around ? This way, killing the baddies would require a bit of thinking in addition to the reflex skills needed to aggro ennemies without dying.

[runevision]

Update: The AI pathfinding is now reasonably stable and I've made a playable demo where you can fight with fireballs against simple hunting enemies. Right now the enemies always know where the player is; later the knowledge of most enemies will be made less global and more based on local memory.

Playable demo:

http://blog.runevision.com/2010/08/eas-demo-of-hunting-ai-and-new.html

I'm thinking that maybe it's easier to discuss gameplay mechanics for agile enemies when having experienced oneself how those agile enemies can navigate around. If you try the demo and have some ideas for how to make it more fun, I'd love to hear it!